Wednesday, February 18, 2009

Pruning: the slowest of the performing arts?

It is early spring, and despite the damp and the chill that characterizes an English winter, I have returned to Great Dixter. 

It was mid-spring when I first arrived last May. Blue skies were the backdrop to the thrill of my experiencing Dixter for the first time. Here I am now in early spring where the skies, a bit cloudier, suspend the damp air within my expanding curls. I haven't had one good hair day since I've arrived!

This visit differs in a very meaningful way. First of all, I got to see my friend, and astute plantswoman, Sarah Carter Roberts. Former Curator of Herbaceous Plants and Outdoor Gardens at the NYBG, she is now living it up in Tidworth, England with her new hubby Giles. Every week she travels to many of the outstanding RHS gardens within her radius to study and learn what makes English gardens tick. She collected me from the airport (the term 'red eye' doesn't do it justice), and we made many lovely detours on our way to Dixter. After a giddy evening, we enjoyed the luxury of working together in the garden the next day.

With what time I have at Dixter during this visit, I too, am taking in all that I can.  What I am appreciating now is seeing how the garden is setting itself up to unfold for the upcoming season. All throughout the garden beds can be seen the very first layers of bulbs clustered above latent perennials. 

Without the perennials and self-sown volunteers disguising their backbone, visibly outstanding are the evergreen plants and shrubs that hold the garden erect.  

The real reason I am here is not to muse about the early signs of spring (big perk, though). I am here to learn more about restricting that explosion of new season growth through thoughtful pruning. There is a graceful art to achieving a vigorous, healthy, and well-shaped plant despite its age or character, and this art deserves consideration. As I instinctively knew, and am discovering here, there is so much more to pruning than what the books say.

At its very basic, the practice of pruning involves removing any DDD (dead, diseased, dying) and crossing branches, or following the thumb rule that declares that no more than 1/3 of the plant is to be removed each year (about the latter: "Rubbish," Fergus says). If you are happy with the basics, great.  But if you desire to work a little deeper than what the basics will yield you, the reward for your efforts will be a fine specimen tree, shrub, or vine.

The pruning of woody shrubs is a fascinating endeavor. I will never admit who told me that "horticulture is the slowest of the performing arts", but it has always stuck, and thoughtful pruning is the poster child for that truth. So as you gaze at your shrub, sharpened Felco's or loppers in hand, ask yourself: WHY am I pruning? WHAT am I hoping to accomplish?

(A word on goals: Unless we are talking about boxwood, "Meatball-ing" is an unacceptable pruning goal. We've all seen it, and some of us might even be guilty.  Amnesty is available, though, even to people like my father who would annually bring my mother to hysterics because he insisted on "pruning" the Forsythia.)  

Rejuvenation, increased flower or fruit production, specific training (pollarding, espalier, hedging), reduction of size, encourage ornamental foliage . . . these are all specific goals that, when pruned with that goal in mind, your plant will respond to. Before cutting branches without intention, really LOOK at what you are about to do, and before you cut, ask this: What will happen next? And in the season after that? Even 10 years down the road? Every pruning cut illicits a growth response from the plant that you can anticipate, learn to envision, and plan for. Cause and effect matters here. Is that dead horse beaten enough? PETA may agree. 

Here are the basic principles that I took home as my souvenirs:
1.) Fergus was careful to guide my first cuts (this is Great Dixter, not my backyard) by asking me to remove the most obvious and benign material first. This consisted of removing any and all spent flowering stems either completely, or cut back to a new strong shoot. STOP, and look.
2.) Next, remove any dead, weak, or insignificant twiggy junk that is growing off of the  stems and larger branches.  This "opens up" the negative space so that you can now more clearly see the inner structure of the stems and branches. STOP, and look.

2a.) You will notice lots of thick old wood, weak and spindly growth, and you will see strong new growth. It is that vigorous new growth that will keep your plant young, that will flower best, and will produce the growth that will contribute to the following year's framework. You may be tempted to cut all the wild new growth down in favor of the older structure that is already there. I've done it, let me admit it! But that is for the short-sighted, which I am no more.  

3.) Identify all the weaker wood, branch by branch, and cut remove that weak wood to the most vigorous shoot. Clean up the stem or branch of any weak wood/stems to ensure that all the plant's energy goes into the desired growth.  This part takes the most time and thought for me. The goal is balance: not just in the actual perception of the shape, but also, a balance of old and new wood.  You can easily remove too much new wood sacrificing flowers and/or fruit. 

About rejuvenation: Keeping the old growth encourages an old and weak shrub. When old growth is judiciously removed according to your rejuvenation plan and vital growth is encouraged, that plant will literally be a fountain of youth. Check this out: just guess how old this Weigela is?

I was astonished (and a little scared, as this was one of my pruning assignments) that it is the oldest shrub in the Long Border, and is at least 60 years old. It has form, it has shape, it has vitality. Fergus keeps these enduring gems in a constant state of rejuvenation--the only way to sustain the valued pieces of this garden's history. 

The difference below may be subtle, but this Weigela is on the 10-year plan.  It will flower well this year, there is a lot of vigorous growth, and the non-productive has been removed. 

Same principles apply to this Viburnum.  The difference is the age and character of this shrub.

After all the flowered,  twiggy, and non-productive wood is removed, a much more open an healthy shrub is achieved.  

What about general maintenance? Let's say you have a vine, such as the Lonicera below, and you want to make sure that it flowers as best as it can. How do you even go about unravelling this puzzle?  It can be overwhelming if you are not clear on WHY and HOW.

Thankfully, the same principles apply: take out all the spent flowering stems (muddies up the form), little twiggy junk (sucks energy away from flowering), and view what is strong and best (new growth with lots of flowering buds).  In the case of this honeysuckle, the growth that is strongest, is also longest.

You can see how much material was actually removed by comparing the two photos. Fergus then loosely tied up the outward-reaching stems to the post using tar twine. This keeps the stems trained, and when in bloom a graceful and arching effect is achieved.

I suppose for me, a few key lessons where learned that have successfully changed the way I think about pruning:

1. Have a plan, and know for what objective you are pruning.

2. Do not be scared.  It will--hopefully--grow back. 

3. You control the plant, the plant does not control you.  This is the essence of ANY gardening, for gardens as we know them would not exist without that crucial human element.

4. Think ahead.  Any pruning cut will have a consequence (desired or not) that will be seen next year, and in following years.

5. Know whether the shrub or vine you are pruning blooms on OLD or NEW wood. 

6. Work slowly--smallest to largest, from the inside out, and in some cases from the bottom up.

7. Really, work slowly.  Resist the urge to get in there and yank out the branch that looks like its "in the way".

8. Do not fight the character of the shrub.  If it is twiggy, it will always be twiggy. 

9. Feeding goes hand-in-hand with pruning.  Ring the base of the newly prunes with a generous amount of compost.

10. Make sure you ladder is secure.

Early spring is the best time to prune plants that bloom on old wood (last year's growth). To all the meatballers of the world--STOP! Once your nausea subsides, sharpen your pruners, and untangle yourself a renewed, vigorous, and well-shaped plant!

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