The Complete Guide to Landscape Design, Renovation, and Maintenance
by Cass Turnbull

PRUNING CANE-GROWERS
When I decided to give my first lecture on pruning, I had to decide what to say. The principles of pruning are the same for every plant, but I knew that I approached a forsythia with a different mental attitude from one in which I approached, say, a star magnolia. I concentrated on different kinds and sizes of branches. With the forsythia I spent most of my time sawing out large canes to the base; I didn't worry about its ability to recover. The magnolia required dainty, thoughtful pruning and was more a matter of art. I realized that there were many plants that I pruned pretty much like forsythias and that I could tell how to approach most plants by simply observing their "habit" or natural shape.

This is how I came to divide plants into three broad categories. This classification is convenient, not scientific, but it will help you to decide how to prune your plants by learning to read their habits. I have labeled these groups "Cane-growers," "Mounds," and "Tree-likes." You can start looking at plants on your block and deciding which type they are. Many plants have an in between habit; just train yourself to observe a plant's character.

Defining a Cane-Grower
Cane-growers include a large category of plants referred to in garden literature as "deciduous flowering shrubs." They are often vase shaped or fountain shaped, with many trunks or canes coming up from the base. The bases of deciduous flowering shrubs are usually a clump. A forsythia is your basic cane-grower, as is a rose. Cane-growers renew themselves by sending up new canes; hence they can afford to lose their old canes to injury or pruning.

Some cane-growers spread by underground stems or roots rather than by staying in one clump. Examples of running cane-growers are bamboo and kerria.

There are also intermediate cane/tree-likes and cane/mounds. More on them later.

Starting to Prune
Deciduous flowering shrubs are chosen and planted mainly for their flowers, although some have a habit and foliage that's interesting, too. Forsythias can look great when in bloom and then pretty uninspiring the rest of the year. Many of these plants have an optimum age of each cane for flower production, say, canes three or five years old. So, by cutting back the oldest canes to the ground level and encouraging some of the new canes, you are planning for good flowers in coming years. This cutting back is not necessary; the shrub will bloom anyway, but it is desirable for those who really care about having the maximum amount of flowers. Taking out one-eighth to one-fifth of the old canes each year will also keep your plant from getting too big, as nothing in there will be more than five to eight years old. While you are pruning out two or three or five of the biggest, oldest canes, take out some of the newest ones, too. Pick only the nicest arching or healthy ones to remain. Cut out some puny, too straight, or too crowded ones, also. On the other hand, if you would like your forsythia to be ten to fifteen feet tall, just let it be.

Looking for Dead Wood
On many of these old cane-growers you will find a lot of dead wood. The shrub can afford to let canes die back because it's easy for it just to send up a new cane as a replacement. Old deciduous flowering shrubs often have big stumps of dead wood at the base. Weigelas and forsythias will show many stumps where old canes were cut back to three inches or six inches. They will be dead and punky or dry as powder. I'll never forget the look on a client's face when I went over to her forsythia and pushed on a giant old hunk of dead wood that just snapped out in my hands at the base. It had looked as if I would have to take a saw to get it out. It was in the winter and she must have wondered how I knew it was dead.

When pruning cane-growers, spend the most time thinning out canes at the base.

Cutting Live Cane
Speaking of sawing, after you prune or push out the dead wood, you will have to saw out some of the big old live canes, too, especially the ones crowding and rubbing in the middle. These are the hardest ones to get at because all the others are in your way. You will have to scoot around the plant to find the best position to get at the target cane. Sometimes it is not possible to saw it or cut it off right at ground level; just do the best you can. Sometimes you have to sacrifice a couple of outer canes that are in the way. But don't risk destroying your shrub to get at the inside canes. When pruning an inside cane, the space is often so tight that you can only saw with the very tip of your saw. Keep at it! When you finally make it through that big old cane and haul it out, you will be amazed and deeply gratified because you have dramatically reduced the bulk and clutter of your plant. You can pull out your cut cane by tugging on it down and out from the base; check to see if it's catching on anything big. Sometimes you can push it up and out. Sometimes, if it's really wrapped around other things (and these canes are the ones you're after) you may have to cut it into smaller pieces where it's hung up. It only takes the removal of a few big canes to alleviate big problems.

A Trained Eye
But, before you cut, you need to train your eye. Stare at your shrub; deciduous flowering shrubs are easier to stare at in the winter when all those leaves aren't hiding the branches. Pick a couple of canes and follow them; see where they go and what they run into. Visualize how the plant would look without this or that cane. Look for canes that are too crowded, or that twist around or that badly rub other canes. Look for canes that start on one side of the clump and head the wrong way through the center and out the other side. Look for ugly branches, by which I mean branches that are too straight (if it's supposed to be an arching shrub). This is a tough one on forsythias and weigelas, because it's the older canes that develop this nice arching habit. The new canes tend to be straighter, with flower buds spaced farther apart. You may encourage some of these young canes to fork and start curving by cutting (heading) at a bud at the height you want. Look closely at these buds. The way the buds face is the way your new branches will go. Visualize! Are your new branches going to go where you want (and not into the center)? Do not be afraid to head back a large cane to a place you intend it to bush out and fill in.

Now that you have been staring at your shrubs for a while, you realize that there are tons of wrong branches and canes. You can't get them all, so pick two or three of the worst ones and cut! Voila!

Plant Size
Cane-growers are good for the novice to work on because they are, generally speaking, really tough stuff. It's hard to hurt them or ruin their shape. In fact you can renovate them by cutting them totally to the ground and starting them over. Really! It's okay! Don't try it with your rhododen- drons, though. (See chapter on renovation). Something you should know about cane-growers and plants in general is...they have a size they like to be, and it's not usually a convenient three feet by four feet. Lots of the deciduous flowering shrubs like to be five to ten feet tall. I remember when my mentor Andrea pointed to some deciduous flowering shrubs (mock orange or Philadelphus,) and said these plants like to be about eight feet tall. I thought, my God, don't plants grow to whatever height I cut them? How will I take care of something eight feet tall? But, really, it's easy, as I found out. It's hard only when you work against what a plant wants to do. When you try to keep a plant smaller than its mature height, it loses its nice natural shape. You must cut off most of its flowers and it turns out that you have to be out there whacking away at it all the time. So, although your cane-growers can take it, don't work against them. Fortunately, horticulturists are breeding smaller varieties of many of our pretty, giant cane-growers like forsythias and spireas, for our smaller yards. If your cane grower is really, really too big, read the renovation chapter.

After taking out the dead wood and some old canes in your shrub, move up top and sort out some (rarely all) of the crossing and ugly branches (use thinning cuts and selective heading). If your plant's tips hang down to the ground, cut them back a bit. If one branch sticks way out, cut it back to a side branch that is the right height. Be aware that there is another workable way to prune cane-growers. The British develop a low (four to twelve inch) framework called a "stool" and cut the canes back to it.

Prune roses as you would other cane-growers, then reduce height dramatically. Gardener shown is trying to locate out-facing buds to cut above.

How to Prune a Rose
When people speak of garden roses, they are generally referring to hybrid teas. These are pruned heavily and greatly shortened to force them to produce bigger flowers and to keep them to a manageable height.

You prune a rose like any other cane grower, only more so. After pruning too big, too small, too crowded branches, by cutting out at the base, you shorten all the canes drastically. You cut to a side branch or promising bud facing, generally, out from the center. Gardeners like pruning roses because it's so dangerous with all those thorns. (You know, some people climb mountains.) In the early spring you find gardeners standing on their heads looking for tiny, swelling pink buds on the sides of canes.

When cutting out rose canes to the base, most people prefer to take out canes which are thinner than a pencil, and a few of the fattest ones. People disagree on how far down to head the remaining canes. But do make the skinnier canes shorter and the fatter ones taller. I like to keep a cane that is as fat as a cigar and about as long. Rose fanciers in the mid-western states will cut them as low as three buds from the ground! One rosarian I know teaches new rose pruners the chant, "You can't kill a rose by pruning it. You can't kill a rose by pruning it," to give them courage.

When you begin to shorten your canes, you will find that the place which seems like the right height usually has a bud facing the wrong way (i.e., facing toward the center), and vice versa. As with most pruning and renovating, it's a matter of just doing the best you can. Pruning instructions are always guidelines, rarely hard and fast rules.

You should also be aware that many roses are grafted. The above ground portion of the shrub is spliced onto a tougher root stock. Sometimes the roots send up shoots of their own, especially after a freeze. You need to cut off these unwanted canes or your rose will revert to the rootstock rose.

Thin out roses and other shrubs, but not too much.

A good thing to remember about pruning a rose or any other cane grower or plant of any sort is not to take everything out of the middle or everything down low; leave something there. We want to thin it out, not gut it out.

There are other kinds of roses--shrub roses, old roses, climbers, ramblers, miniatures and floribundas, to name a few. You prune them less severely. For people interested in a more in-depth description of rose pruning, I suggest Brickell's Pruning, New York: Simon & Schuster, 1979. Usually a little light thinning and sorting out will suffice, however, for the average home owner's non hybrid tea rosebush.

Some cane-growers are vase-shaped and grow from a clump. Others increase in width by "running" with their roots. Reduce width of the latter by diffing and cutting back roots to desired shrub sized.

Pruning "Running" Cane-Growers
There are many other miscellaneous cane-growers that are not deciduous flowering shrubs. These are things like bamboo and Oregon grape that spread with runners. Heavenly bamboo (Nandina domestica) stays in a clump, but is not deciduous (it usually keeps its leaves all winter). Kerria is deciduous and flowering but it runs. You can tell the type by observation. All cane-growers look better if thinned by cutting some canes to the ground, unless you are using them as a hedge. There is a general rule about plants to the effect that you can encourage either tall, thinned out plants or low bushy ones. When you cut them down drastically to reduce height, they tend to get busy and send up new canes and new side shoots to make up for it. A combination of thinning and shortening is usually best, depending on what you are trying to do. Plants that run, which is to say ones with a mat of roots spreading across the top layer of dirt, can be easily reduced in size (width) by grubbing out the roots. For bamboo, this works only on new growth. The old growth is about as tough as reinforcing steel bars. To reduce your mahonia (Oregon grape) or kerria, loosen the dirt with a shovel and pull canes up and back toward the center of the plant. Use an old pair of loppers (so you won't mind if they get dull cutting down in the dirt) to cut the roots where they're too matted or well rooted. Prune with vigor! You won't hurt what's left.

Pruning "In-Between" Plants
Many other plants that I have categorized as "mounds" or "tree-likes" have a sort of in between habit where they, too, will benefit from your cutting some canes down to the ground. A lilac, which is mostly tree like, sends up suckers or canes from the base. Usually, you cut these out, but you may want to choose one to develop into a nice new trunk. Or, you may wish to renovate your lilac slowly by taking a big cane down to a side branch or out at the base. In fact, many people treat lilacs as cane-growers--sacrificing branch patterns for lower blooms, pruning them almost like a forsythia.

SUMMARY
Cane-Growers: Thin out canes to the base. Cane-growers are tough.
If it's not broken, don't fix it.
Shrubs and trees don't need to be pruned.
Each species has a size it likes to be--its "mature" height. You cannot usually keep a plant smaller than its "mature" height without doing great harm to its looks, its health or your own pocketbook.
Cane grower pruning punch list:
1. Stare at your shrub.
2. Take out all dead wood--always do this first.
3. Take out some (one-eighth to one-fifth) of the oldest canes to the base and some of the puniest new ones every year, if you like.
4. Pick out the worst looking canes that rub or cross each other, that look sick, go the wrong way, or are ugly.
5. In general, prune to open up the center.
6. Tidy up the rest of the plant, always cutting to a side branch or bud (node).
7. Prune with vigor!

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