Makenzie, Author at American Rose Society

A Little Botany

Jul 17, 2024 | BASIC ROSE CARE

by Rich Baer, Master Rosarian and Botanist, Portland Rose Society

This article was originally published in The Portland Rose Chatter, February 2021.

As a person who grew up as a plant person and obtaining a plant education including advanced degrees in Botany, I am very attuned to the lingo of the plant world. As with any specialty there are a lot of words that are unique to the field and are often misused. As long as it does not lead to any communication problems, it really does not matter. If roses have thorns or not is not a major problem, because we all understand what roses do have and what exactly we call them, (the correct word for them is prickles), causes no problems.

One little phrase for describing the rose classes does however bother me and I have spoken about it a number of times and that is referencing roses that have one row of petals as being single petaled roses. This problem came from exhibiting roses. One rose in a vase for entry purposes is referred to as a single rose. So, then what do we call a rose that has four to eight petals in one row around the bloom? To differentiate it from one rose in a vase it began to be referred to as a single petaled rose. The picture to the right is what a collection of four single petaled roses would look like. In nature there are no single petaled roses. The minimum number of petals in any rose currently known is four which is the number of petals in Rosa Omeiensis Pteracantha, also called the wingthorn rose. This is the rose with the very large red prickles which is the reason those who grow it do so. For the sake of exhibition the American Rose Society has defined a single rose as one which has between 4 and 8 petals. Personally, I find single roses to be very attractive and probably have as many as 20 or more of them in my rose collection.

Every day that we do go out into our rose gardens we observe the roses growing. I believe that this year (2020) they have done exceedingly well with great vigor and many many blooms. However, do we ever look at that rose growth very carefully and up close? As a botanist I am always watching to see exactly what my roses are doing so that I can gain more appreciation for what I am seeing. A number of visitors to my garden this year have commented on how tall my roses are. I usually reply that because I look at them more as a garden, how high the flowers are is not a concern. The picture on the right represents a typical new stem growing from an old stem at the point that the last deadheading was done.

The stem typically grows rather rapidly, producing leaves at intervals from nodes along the stem as it grows. At each of these nodes, at the base of the leaf is a vegetative bud. At this point in its growth you will never see any side shoots developing from this shoot. If you look closely at a stem you can find the tiny buds at the very base of each leaf located along the stem. At the very tip of this stem there are thousands of cells called the apical meristem. These cells divide into non differentiated cells. That is, they are not leaf cells or stem cells. They will eventually become specific cells that will grow into leaves and other tissues along the stem as time passes. But back at the tip of the stem, the meristem cells continue to divide and at the same time they are producing new cells, they are also producing auxin, the most well know plant hormone. This auxin travels down the stem and its presence prevents any of the new buds that have formed at the nodes from growing. This is the reason that you rarely see side shoots on the newly developing canes. At a point in time that is determined by several factors, including environment and hormones the vegetative stem will become reproductive. The meristem cells produce cells that become the forerunners of a flower. Once the flower bud begins to grow it occupies the tip of the stem and there are no longer any meristem cells. All of the new parts have been produced by the meristem cells, the stem and foliage beneath them and the growing flower bud above them. The picture “reproductive stem” shows the existence of the flower bud from the tip of the stem. When you can first see the tiny bud it is the first time you will notice that the stem is about to bloom, but the production of this new bud has been going one for quite a while. With the disappearance of the meristem cells there is also no more production of auxin at the tip of the stem. The reduction in the concentration of auxin in the stem allows the previously inhibited buds near the tip of the stem to begin growing. Depending upon the variety of rose, the number of these stems which will begin growing can vary. You probably know that part of the definition of the hybrid tea rose is one that grows with one flower per stem. Without disbudding, you rarely get just one bud and flower per stem, you usually get more than one bud at the tip of the stem.

The picture left represents what a single bloom looks like. There is the developing flower which is attached to the plant by a stem. However, this attaching piece is not a stem but varies from any other stem on the plant in several ways. This structure also has its own unique name and is called the “peduncle”. The most obvious difference you can see by looking at it is that it has no nodes. No leaves have developed along its length. It does however originate at a leaf node, much as any other stem on the rose plant. If you deadhead by snapping off the dead flowers this peduncle usually cleanly snaps off at its origin when you push it over. If you do remove dead flowers this way, just grasp the peduncle between thumb and forefinger and bend to the left or right. After it breaks off, look at the tip of the stem left on the rose bush and you will see at its very end a leaf. It may be a regular leaf that you will recognize as a leaf, or it may be just a little green fold which does not look like a leaf but it is. If you tried to break a rose stem you will not find that it will cleanly break away from the plant as does the peduncle. Sometimes the peduncle will not snap off cleanly but usually it does. If you have tried deadheading this way you know what I mean.

Almost always after you see a stem become reproductive with a flowering bud at the tip of the stem, you will see additional buds beginning to grow as well. With the absence of auxin to inhibit the growth of the side buds on the rose stem, they often begin to grow. As you can see in the picture on the left we often see side buds beginning to grow from just below the peduncle. In this case, you can see the two nodes, they are at the base of the leaves projecting to the right and left. From the very top node the peduncle of the new bloom is growing, as is one of the side buds. In hybrid tea roses it is often the norm that at least the top two nodes will produce side buds. If you could watch the progress microscopically, what you would see would not be just the emerging of the two side buds. The bud at the base of the leaf would begin to grow just like any bud on the bush. However, it would not grow like a stem for very long. It quickly changes to a reproductive stem and begins to produce a peduncle and bloom. However, the stem often will grow enough before this happens to produce enough normal rose stem to have two or three leaves and thus nodes. So, each of these side buds is produced just like the major bud that is at the tip of the stem. In most cases the buds at the nodes on these side bud stems do not grow, so we have the main bud with an indeterminate number of side buds.

Everything is the same for each of these side buds as it is for the major bud that originally was produced. So we have stems with tiny leaflets at two or three nodes below the peduncle and bloom. The same thing can happen here that happened to the main stem, side buds can begin to grow. They can grow with the same results as we had before.

They will produce very small stems that can have several nodes and tiny leaves and a bud and peduncle on their end. This can lead to a very large spray of roses being produced at the end of the main stem if they are allowed to proceed. This is what happens in the case of many of the floribunda roses and other roses which are grown as landscape roses for color.

The picture above depicts the blooming of one such rose called Greetings, a shrub rose from Jackson and Perkins. The main bud can be seen in the center and is showing color. You can follow the progress of this spray in the stems below. Below the main bud side shoots began to grow and produce stems and buds. Then from those shoots additional side shoots grew and produced buds and there are places in this spray where there is a fourth group of buds being produced. All of the stems and peduncles grow from a node that is marked by the presence of a rudimentary leaf, but a leaf just the same. There are no peduncles which originate from other peduncles and there are no stems that do not originate from other stems.

In this case the original terminal bud will bloom first, and then all of the first wave of side buds will bloom at the same time. Then each additional wave of buds will mature and bloom in sequence. That is why disbudding large sprays can become tedious to the exacting exhibitor. But in the garden, we just let them bloom to produce the great color spots that they can become.

There was a reason for trying to establish how flowers are produced on the ends of rose stems and the importance of the peduncle. The peduncle exists from the bottom of the bloom to the first node from which it came. In this case the node can be easily seen because there is a leaflet growing from where it emanates from the stem. There is no incidence in which one peduncle arises from another peduncle, they always begin at a stem node and end at the base of the growing flower.

Plant Taxonomy is the science that finds, identifies, describes, classifies and names plants. Every part of the plant is examined in determining how to classify it. The reproductive parts are very important in the classification of plants overall. The way the flowers are arranged when they bloom is very important as well. In roses, the presentation of the flowers is very much at random. The vegetative tip produces a bud and then all sorts of different combinations can occur below the first bloom. In many plants the presentation of the blooms is not at random, but occurs in a specific way for any one variety of plant and the presentation is called an inflorescence. The names of most of the different types of inflorescences are probably not known to many, but there are a few that are familiar. Probably the most common would be the head. This is the type of flower presentation in plants such as sunflowers. There is one peduncle formed at the tip of the vegetative stem, just like in the rose, however that peduncle begins to divide and re-devide many times over. The stems that are produced by this division of the peduncle are called pedicels. In the case of the sunflower each of the pedicles produces a flower at its tip and they grow such that the structure that we know as a sunflower head is formed. In the representation to the left are many of the different ways that plants produce their flowers. In any one type of flower, sunflower for example, every time the vegetative stem becomes reproductive and produces a reproductive peduncle a head will be the result. The type of inflorescence formed by any one variety of plant will always be the same because it is in the genetics of the plant to grow that particular way. A rose may randomly produce a spray of blooms that resemble one of these classic inflorescence types, but it will not be a repeatable event. The occurrence will be strictly accidental since the genetics of the rose cause it to produce its flowers in the way previously described with each bloom arising from the stem of the plant on an individual peduncle.

Another common type of inflorescence is the umbel. The peduncle that is produced branches into any number of different pedicles each having a flower at it tip. Probably one example known to gardeners would be either the carrot, or Queen Anne’s Lace. You can turn the flower over, the inflorescence, and see how the peduncle is divided over and over again producing the classic look of the Queen Anne’s Lace flower head. In each of examples in the diagram you will notice that the peduncle is emerging from the last leaf on the stem and then there are no leaves on it as it grows and divides.

As a botanist I observe what is going on in the garden at a little different level than the average gardener, which is not necessarily good or bad. But I think that the more you know about the things you enjoy, the more that you can enjoy them. I have a number of plants growing in pots that I am able to observe closely almost every day of their growing cycle, including one that has fascinated me for the last three years. When I first saw Asclepias physocarpa in a catalog, I knew I wanted to experiment in my garden with it. The taxonomist recently renamed it to Gomphocarpus physocarpus, but it is the same plant. It has many common names, including balloon flower, and family Jewels tree. But it is a member of the plants that Monarch butterflies feed on. I would like to see them in our part of Oregon. I have never seen one here in my over forty years of gardening here, but there is always hope. This plant produces flowers in an inflorescence known as an umbel, you can find it in the diagram of types. The peduncle originates from a node on the stem of the plant and grows and then it begins to divide into pedicels, normally with this plant there will be five to seven, each of which will bear one flower. I have nine of these plants growing around the yard, all of which are over 8 feet tall and there are literally thousands of blooms on them and every one of them is produced by exactly the same type of structure, the umbel. There is no randomness to all of the flowers, every one of the inflorescences looks exactly the same. So, you see that it certainly is not a random occurrence that the flowers are produced in umbels, the genetics of the plant makes every one of them the same. Going back to the rose, you might find five or six blooms that are presenting themselves such they look like they are an umbel, but it will certainly be random and will not repeat with any regularity and besides, each one of the blooms would be on its own peduncle.

The usage of the word inflorescence has become the dominant way that rose sprays are described in the judging guidelines for roses. I believe that the term is being misused and all collections of rose blooms on one stem should be referred to as sprays. In referring to the individual blooms of a spray the term floret is often used to describe them, and I believe that botanically this is incorrect as well. The word floret botanically refers to the tiny flowers of some grasses. It is correctly used for the flowers of cauliflower or broccoli or members of the compositae family like sunflowers.

WHAT COLOR IS THAT ROSE?, OH, NO COLOR!

Back when I worked for Edmund’s Roses when they were in Wilsonville, Oregon I got to talk to many people and try to answer their horticultural questions. One question often repeated was about rose colors. Is there a blue rose, or is there a black rose?

I could understand people wanting a blue rose because it is the only color that roses do not come in. However, black! If you had a black rose in the garden there would appear to be a hole in the bush where the flower was. Black items by nature do not reflect any light so you would not be able to see a truly black rose. Later I was honored to be part of the production of a book called “The Quest for the Black Rose” by Ingrid Verdeem around 2006 by describing many roses which were considered near black. It is still available used on e-bay for around $80. It was a giant of a book at the time measuring 17 inches by 13 inches and it does not fit anywhere on my bookshelves. I however I have a special place for it. A couple of the prominent and known roses to be discussed were Black Baccara by Meidiland, and Ain’t Misbehavin hybridized by Sean McCann.

When Sean’s rose was released around 1990 it was hailed as being very close to a black rose, but in reality it is consistently a very, very dark red. One of its parents was Black Jade, a long time favorite in our garden for being very dark red as a miniature. Last year when a planted rose seeds for the first time, one of the roses I took seeds from was Hoot Owl a Jerry Justice hybrid which is a medium red single miniature with a white eye. It was selected because it had an abundance of nice-looking hips when I pruned it in February. I was able to get a number of plants from the seeds of Hoot Owl which spanned the color spectrum from white to dark red, all of them singles. Because the plants were still small last fall, I moved a number of them into my garden shed where I continued to grow them under lights. What a surprise it was on the morning of January 21st, when I went out to water them to find a bloom on hoot 4 which gave me a thrill of seeing what I considered the first truly black rose I have ever seen. It was beautiful in its own way, but mostly for its uniqueness. This seedling had bloomed earlier during the summer outside and it very much resembled Ain’t Misbehavin when grown outside with a good dose of ultraviolet rays. But grown inside, it was a whole different rose. I do not think will bes, but it sure was fun seeing what I believed was a first black rose. Just as an aside, the picture was not underexposed to make it darker than it actually was, and you can tell that by the naturally colored green in the leaves.

Photos by Rich Baer

Tips, Tricks & Hacks of Rose Care – Tool Talk & Spring Tips

Jul 17, 2024 | BASIC ROSE CARE

This article is from Roses & You, March 2019

First thing… Before gardening season starts, clean your pruners. Oven cleaner works very well for removing the built-up blackened sap from the blades of your pruners. Spray the cleaner on the blades and let it soak for five minutes or so, then wipe them off. If there is still more residue, spray them again and repeat. If the buildup is not all coming off, you can use steel wool or a scotch brite pad to help remove it. Rust can also be removed this way. Sharpen the pruners next. I use a Barnel diamond edge sharpener I had gotten from the Harlane Company- www.harlane.com. Frank Benardella said he used a diamond chip nail file which worked very similarly. When sharpening, only do the edge from the angled side and match the angle which is on the blade. After you’re done with the beveled side, turn the pruners over and remove any burrs on the flat side by holding the sharpener flat against the blade very lightly pulling it toward the sharpened edge. Once the pruners are sharpened, spray them with WD-40 or a similar lubricant.

Being left-handed, I use a Felco #9 pruner. I found no matter how sharp a right-hand pruner was, the cut was not always clean, this solve that problem.

After breaking or seriously dulling pruners or loppers, I think I finally learned to use the right tool when pruning heavier or hard canes. My arsenal now includes ARS 2’ extended handle cut & hold pruners, a 15-inch Fiskars power gear lopper, 32-inch Fiskars power lever loppers, 5’ Fiskars pruning stik®, and a folding Stanley pruning saw. The extended handle pruners and pruning stik® are very helpful for pruning climbers or large shrub or OGRs, because you can reach most tops without a step stool or ladder. The older we get, the less climbing we want to do.

A good pair of leather gloves is also recommended too, the gauntlet styles are even better. If yours get like mine, with holes in the fingers, consider replacing them. Anyone who does not wear glasses should also consider eye protection when trimming or pruning your roses. Canes have a habit of whipping in the wind or snapping back toward you, and you want to protect your eyes!

I have always used cotton twine tying up my climbers. It last for about a year, so I usually retie them each year when I prune. One year I did not, and my huge Laguna climber crashed to the ground. Now I make sure I use a heavier paracord, which I got at Home Depot, to secure the main canes on my large climbers. This will never break, and I have been able to untie it fairly easily and reuse it to fasten the canes year after year. It is available in tan or green camouflage, so it blends in very well. I still use the cotton twine for smaller canes or temporary fastening.

Before we get busy in the garden, spring is a good time to check to see if you have had a tetanus shot in the last 10 years. It is recommended every 5 years, but no more than 10. If not, you should schedule one as tetanus is a soil borne disease and it is easy to get scratched when working around roses.

Basic Pruning Principles

Jul 17, 2024 | BASIC ROSE CARE

To ‘prune’ – “to lop or cut off the superfluous parts, branches, or shoots (of a plant) for better shaped or more fruitful growth; to shape or smooth by trimming; to cut off or cut out (dead branches from a rose bush).” In colder climates the removal of dead branches may well be the prime activity, but in warmer climates the main emphasis is certainly on the opportunity to shape the bush for the Spring bloom. It is this practice of regulating the shape that can enhance the landscape ambiance of the rose garden and ensure a vigorous first bloom that makes the effort all worth while. Second, the act of pruning if approached logically can encourage new basal growth from the bud union – usually regarded as strong evidence of good health. Third, the removal of old wood and damaged or diseased parts can allow a recuperative process to take place for increased growth power.

This removal of branches and sometimes old canes serves as a form of dormancy in warm climates since it cannot be achieved naturally. Since it has been proven that it is a healthy habit to allow rose bushes a period of non-production, the act of pruning does permit a time period where the governing biochemical processes are slowed down and redirected to produce that first magnificent spring bloom. In greenhouse production, for instance, the rose bushes are never given a formal prune to allow them to rest, but are groomed continuously to produce flowers for certain special holidays and events. Within a few years they burn out or become poor performers and have to be replaced. Allowing a rest period each year prolongs the life of the bush and makes sure that bloom quality and quantity is maximized for the home garden. It is often remarked that the first bloom cycle is the most attractive and the spring rose shows certainly prove that conclusion. The growth pattern in that first bloom cycle is the beneficiary of the forced redirection of stored nutrients via proper pruning.

EQUIPMENT NEEDED

Above all else, investment in a pair of high quality pruning shears is mandatory. After all the expense of buying the rose bush and the planting process, you have already invested about $10.00 to $20.00 per bush. A good pair of pruning shears from Felco® (Swiss Import) or Corona® (made in California) will cost between $25.00 and $40.00. There are other manufacturers, but these two companies have track records for providing the highest quality products. The pruning shears should be the scissor type not the Anvil type. Felco has a special hand grip designed for left-handed people, swivel handles, and even a model with removal blades for maintenance. For miniature roses, there are smaller versions of these pruning shears which rely on a smaller blade surface.

For removal of large woody canes at the bud union a pruning saw from Corona will allow access for flush removal. Attempts to use pruning shears for these jobs usually results in damage to the bud union. It is best to approach cane removal with a proper saw designed specifically for the job.

For cutting large diameter canes a pair of lopping shears with 18″ handles can facilitate the cutting without placing too much pressure on your hands. Again, attempts to cut large diameter canes with pruning shears will require a lot of extra strength in your hands. The lopping shears with long handles solve the strength problem and makes the cut clean and sharp.

Invest in a small wire brush (about 2″ wide by 3″ deep) to help remove loose bark away from the bud union. Such treatments can encourage basal breaks and stimulate new growth since growth often finds it impossible to break through the heavy tree-like bark encountered on older bushes.

Finally, save on profanities while pruning by buying a good strong pair of thick leather gloves that are puncture proof. There is nothing so irritating than a thorn under the nail to cause a string of words rarely heard in a rose garden!

THE ANGLE TO CUT

By far the most important technique to master in pruning roses is the correct angle and direction of the primary cut. The final pruning cut should be made at approximately a 45 degree angle, about 1/4″ above a leaf axle where there is a dormant eye. (See picture at right.) If the bush has foliage present, the cut location is easy to find. However, cuts are often made further down canes where there is no foliage to guide you to the appropriate cut. Under these circumstances look for the dormant eye on such canes by locating where foliage was once connected. The eye is normally visible as a slight swelling above the surface of the cane. Making these primary cuts is the key to success in pruning. To help understand the importance of making such cuts, the following diagram illustrates five ways to perform it, but only one that is correct. The cut should be made such that the growth that will eventually emerge from that eye will naturally point away from the center of the bush. This deliberate planning of new spring growth patterns is what gives the rose bush a pleasing overall circular shape that spreads from the center outwards. Such cuts avoid the growth from being directed inward and colliding with other stems. The basic logic behind making the cut slope down and away from the eye is that the excess natural sap that will rise to seal the cut can pour down the opposing side of the cane and not interfere with the developing eye. Master these two simple rules and the shape of your spring growth will be guaranteed to give an overall pleasing growth habit for the rest of the year.

1. The classical correct cut.

2. Cut too far above the eye.

3. Cut too steep an angle above the eye.

4. Wrong direction of angle cut.

5. Cut was badly executed, but more seriously a new pair of pruning shears is required.

GENERAL TIPS ON PRUNING

A number of general points of advice for good pruning can be outlined.

1. Always prune cut to good healthy tissue easily recognized by the green bark on the outside of the cane and white pith core revealed after the cut is made.

2. To accelerate the sealing process after the cut is made, a drop of carpenter’s glue (or nail polish or black pruning sealer) can ensure a quicker recovery as well as provide an instant protective barrier against cane borers (those insects that drill several inches into the white pith core and deposit their eggs.)

3. Prune to ensure the center of the bush is open for maximum air circulation, i.e., canes emanate from the bud union like spokes of a wheel with no cross-overs or interferences. Imposing this type of architectural structure on the rose bush will help prevent powdery mildew in the Spring via good air circulation within the bush. Additionally the overall shape of the bush will be pleasing to the eye when blooms finally appear.

4. Plan to remove all weak or twiggy growth on main canes that is and not capable of sustaining a reasonable thickness of stem. Hybrid tea blooms need a stem about pencil thickness or greater for support.

5. Remove suckers if present (i.e. growth from the root structure below the bud union). Remove them from as close to the main root cane below the bud union as possible. Suckers can only appear on varieties that have been budded such as hybrid teas. The sucker represents the growing habits of the understock used for budding, usually Dr. Huey. If allowed to grow, the sucker will eventually take over the whole bush and suppress the variety budded onto it. Understock varieties can easily be recognized by their flowers (pink and five to twelve petals in the case of Dr. Huey).

6. Remove old canes that appear woody by sawing them off as close to the bud union as possible. Make this cut clean and smooth. Should any stubs from bad cuts made last year remain, saw them off cleanly. Finally, apply a wire brush to the woody epidermis of the bud union to loosen and remove any dead tissue to promote basal activity.

7. Remove any remaining foliage from the canes after pruning has been completed, and clean up around the bush discarding all foliage as trash.

Basic Rose Terminology

Jul 17, 2024 | BASIC ROSE CARE

When speaking about roses it makes it much easier if all of us use the same terminology. The following is a list of basic terms used to describe rose plant parts. It is a lot easier to understand what someone is talking about when they say “sepals” rather than “… you know, those little green things just under the flower …”

Anther – The upper portion of a stamen which contains the pollen sacs.
Apical Meristem – Non-maturing cells located at the tips of shoots and roots which produce the plant hormone auxin.
Auricle – The ‘ear-like’ projection found on the tip of the stipule.
Auxin – a plant hormone that regulates the bloom cycle for rose buds.
Axil – the angle on the upper side where the leaf and stem join.
Axillary – A term applied to buds or branches occurring in the axil of a leaf. These buds begin to grow after pruning or deadheading.
Bark – The outer layer of the stem of a rose.
Bud – An embryonic shoot that may eventually produce either flowers of foliage.
Bud Union – That area between the roots and the stems where the bud of the desired variety was grafted onto the rootstock.
Bract – A leaf unlike the ordinary leaves which is usually smaller or of a different shape, growing from the peduncle just below the flower.
Calyx – The first of a series of flower parts growing from the peduncle, composed of sepals, usually green and leaf-like.
Cane – The stem of a rose, either the main stem (which then becomes the trunk) or lateral stems or branches.
Carpel – An organ bearing ovules along its margins; part of a compound pistil.
Compound Leaf – A leaf composed of two or more parts or leaflets. Rose leaves are pinnately compound.
Corolla – The second of a series of flower parts growing from the peduncle, composed of petals.
Double – Referring to how many petals the rose has – usually between 25 and 45.

Filament – The stalk of the stamen which supports the anther.
Floral Tube – A cup-like structure formed by the fusion of the basal parts of the sepals, petals and stamens. Don’t call it a ‘calyx tube.’
Fruit – A ripe ovary containing seeds and any adjacent parts.
Hip – The fruit of the rose which contains the seeds.
Leaf – An organ arising laterally from superficial tissues of a shoot apex. It is usually flat and may be simple or compound.
Leaf Scar – A mark left on the stem where the leaf detaches. There is a bud just above each leaf scar.
Meristem – Tissue composed of cells that do not mature, but remain capable of further growth and division. Present in growing tips.
Mixed Buds – Buds that produce both leaves and flowers; usual type of bud on roses; present in leaf axils.
Ovary – The swollen basal portion of the pistil containing the ovules or seeds.
Ovule – A structure containing the embryo sac, nucellus, integuments and stalk. After fertilization this develops into seeds.
Peduncle – The main stem of a an individual flower or of a spray.
Pedicel – The stem of an individual flower in a spray.
Perianth – The collective term for the calyx and corolla (sepals and petals) combined.
Petal – One of the units of the corolla of the flower. Roses have from four to over 100 petals, depending on the variety.
Petaloid – A transitional phase between petals and stamens. Petalloids are visible in single and semi-double roses as deformed-looking petals in the center of the rose.
Petiole – The stalk of the leaf.
Petiolul – A subdivision of the petiole which connects the lateral leaflets to the petiole.
Pistil – The central organ of the flower composed of one or more carpels and enclosing the ovules.
Pith – The soft inner portion of a rose stem.
Pollen – The granules within the pollen sacs containing genetic information used for sexual reproduction.
Prickle – A spine-like superficial outgrowth of the stem. Roses have prickles, not ‘thorns.’
Roots – The underground parts of the rose used for support and to absorb water and nutrients.
Rootstock – The cultivated roots of a rose which will be implanted with a bud from another variety (grafting).
Semi-double – Referring to how many petals the rose has – usually 12 to 25.
Sepal – One of the units of the calyx. These are the green coverings of a flower bud that open to reveal the petals of the rose. Roses usually have 5 sepals.
Single – Referring to how many petals the rose has – usually four to eight.
Spray – Several flowers buds which arise from one peduncle and develop into many flowers on short pedicels.
Stamen – The organ of the flower producing pollen, composed of an anther and a filament.
Stigma – The top of the pistil, the part that receives the pollen grains.
Stipule – A leaf appendage that is usually present in roses on the petiole where it meets the stem.
Style – The part of the pistil that connects the ovary and the stigma.
Terminal – A term applied to buds occurring at the end of branches. The end or tip.
Thorn – A branch of a plant that becomes woody, hard and pointed. Cactus plants have thorns, locust trees have thorns. Rose do NOT have thorns as the ‘prickles’ on a rose do not develop from ‘branch’ tissue.
Trunk – The main stem of a rose, the cane that later produces all the side branches or lateral canes.
Vegetative Bud – A bud that produces only leaves and never flowers. Roses do NOT have vegetative buds.

Food for Thought about Fertilizing Roses

Jul 17, 2024 | ADVANCED ROSE GROWING

Nanette Londeree, Master Rosarian, Marin Rose Society

We gardeners routinely describe fertilizing as “feeding” our plants, but that’s not really accurate. Plants “feed” themselves, producing their own food in the form of sugars through the process of photosynthesis. We add nutrients, chemical elements necessary for plant growth, to supplement those naturally occurring in the soil. Consider how Mother Nature does it in a forest – fallen leaves and dead plants slowly decay; through lots of biological activity, their nutrients go back into the soil and are available to, once again, be taken up by living plants. By fertilizing, we’re doing the same thing – making nutrients available to the plant via the soil. Fertilizing is all about enhancing the soil, in fact, a common definition of the word fertilizer is, a substance used to make a soil more fertile.

What you see going on with your roses above the ground is largely determined by what goes on below your feet; the top four to eight inches of soil is where plants mostly get their nutrients. No matter how much you baby your roses, if the soil isn’t functional and healthy, it won’t matter much. The living component of soil is perhaps the most important to overall plant health. A single spade full of rich garden soil contains more species of organisms than can be found above ground in the entire Amazon rain forest. Commonly referred to as the soil food web, the vast community of organisms live all or part of their lives in the soil. All plants depend on the food web for their nutrition. Managing for soil health is about developing and maintaining a suitable habitat for the many creatures that comprise the soil food web.

BELOW: Hendrikus Organics

Many gardeners fertilize based on the calendar rather than what is actually needed by the plant. Do you know if the nitrogen, phosphorus, and potassium are actually low in your soil? Have you confirmed that magnesium is lacking before adding Epsom salts? You can save yourself time and money by testing your soil with simple test kits; when you know what is deficient, then add just what’s needed. More is not better with many fertilizers; too much of certain elements can result in damage to plants or soil organisms. The next time you’re thinking about fertilizing, consider a few things:

What does your soil need? Is it low in all the major elements, nitrogen, phosphorus, and potassium, or just one of these?
Will adding the material result in too high a concentration of a given nutrient?
Will the material added to soil provide organic matter that is beneficial to the organisms in the soil?
Is the material safe for the soil food web, pollinators, or other beneficial creatures?
Could the material contaminate groundwater, or result in pollution of watershed through runoff?

Included below are some common materials routinely used to “feed” roses; a few are touted to do great things for our beloved flowers, but is that really true? Read on and you decide:

Alfalfa (Medicago sativa), is an herbaceous perennial plant in the legume family. In addition to low levels of nitrogen, phosphorus, and potassium, it’s rich in protein, vitamins and minerals and breaks down slowly in the soil. It contains triaconatol, a naturally occurring fatty alcohol that is a growth stimulant. It can trigger new basal breaks – that desirable new growth at the bud union or base of the plant, in addition to increasing overall plant vigor and flower production. Be aware that the succulent new growth produced can be an attractant to aphids.

Bone meal is primarily calcium and phosphorus, two elements required for plant growth and that are usually in adequate concentrations in garden soil. Phosphorus, from bone meal or other sources, does not stimulate plant growth or promote flowering; it is only a mineral, not a plant growth regulator. High concentrations of either mineral can be a problem. According the American Rose Society’s (ARS) Consulting Rosarian Manual, symptoms of too little phosphorus: “Older foliage drops without turning yellow. Leaves are dull gray-green in color. Buds slow to develop, leaf edges of older leaves may cup down.” Gardens in high rainfall areas will likely need more potassium and nitrogen, but phosphorus is rarely ever limiting to plant growth in non-agricultural soils.

Epsom salts are the naturally occurring mineral magnesium sulfate. In general, magnesium plays a role in strengthening plant cell walls, allowing the plant to take in the nutrients it needs. The first symptom of a magnesium deficiency in roses is a reduction of leaf size, followed by entire leaves being chlorotic with yellow between veins. The routine addition of Epsom salts can lead to salt accumulation in the soil and create toxic conditions. Roses are not salt-tolerant; symptoms of salt toxicity include leaf tip dieback, marginal leaf chlorosis and necrosis (or burn). In an evaluation of Epsom salts uses in gardening and the often-claimed growth promoting benefits for roses, Linda Chalker-Scott, Ph.D. from Washington State University Extension Service notes “There is no published, scientific research on Epsom salts effects upon roses. The origin of these “research-based” recommendations is unclear.”

Controlled release fertilizers can appear to be a huge benefit to the gardener. They consist of water-soluble fertilizer encased within a polymer coating, forming a round prill. The polymer coating has small holes in which water passes into the prill, solublizes the fertilizer and then the fertilizer slowly leaches from the prill. The rate of the break down and release of nutrients is impacted most by soil moisture and temperature. Moisture is needed to begin the release of controlled release fertilizer. If the soil dries out, it can greatly reduce the amount of fertilizer released.

Multi-purpose products, often marketed as “All in One” or “3 in 1” contain a mixture of fertilizer, insecticide, and fungicide. Using this type of fertilizer product when there is no specific insect pest or disease present adds pesticides to the soil for no purpose, may negatively impact soil organisms, bees and other pollinators, and is much more expensive than single use products.

Remember, Healthy soil = productive healthy roses!