Thursday, April 19, 2012


     I think I have huffed and puffed about pruning long enough for one season. Besides, it is now that time of year where I am too busy to think, let alone opine in public.

     We have now passed the average last frost date in our area, and that means all but the most tender stuff can be planted without a lot of worry. It is like playing the black at roulette now, without any of the anxiety involved with playing a number. So all of us with cabin fever want to get out there and start new life in the plant kingdom.

     Part of my job is to try to convince you to put off that exciting planting day and do boring stuff instead. Especially if you are planting an entire bed, this is a once in a lifetime opportunity to improve your soil without tearing up all your plant roots.

     The soil around Chicago, at least on the Illinois side, is some of the best anywhere, provided some construction crew has not destroyed it. But is has two features that make it less than perfect: it is a heavy clay and it tends to be alkaline. Native plants have no problem with this, but many other plants do, including vegetables.

     The first and central amendment that everyone can use is compost. It is almost impossible to put too much compost in your yard. In fact, if you ever have to fill a low spot, please do not ever add "topsoil." Most commercial topsoil has been sifted through a screen to remove rocks and twigs and to make it soft and crumbly. But it only takes a couple of rains and a few footsteps for it to turn into that same old clay we know and love. Instead, get a blend of topsoil and compost...and then add more compost on top. With all that organic matter, you should expect the soil to settle a bit over time, so spread it slightly higher than you want it to end up.

     Compost breaks down over time and adds nutrients to the planting zone, as well as providing a good environment for all sorts of beneficial organisms in the soil. With enough compost added, you will not have to use commercial fertilizer at all.

     Moreover, all those bits and pieces create little voids around them that allow air and water to penetrate the clay and improves drainage as well as allowing more nutrients to reach plant roots.

     I can pontificate on this subject as much as on pruning. But if the clients now waiting  for me  caught me spending too much time scribbling,  their patience would evaporate, and I would be in big trouble.

Sunday, April 8, 2012


Now you can see that the pruning here is more elaborate than simply cutting stems off at the ground.
    To pick up where we left off, if you cut 1/4 of your stems to the ground each spring, four years from now you will end up with a shrub whose effective age is 4 years, rather than 40. If I could figure out a way to do that for people I would have my own full-time gardener and condos on at least three continents.

     For those of us with over-sized shrubs, however, more may be needed. In addition to cutting older stems to the ground, you need to down-size the stems you keep. For trees and single stem shrubs, that is your only route.

     Before I wax mystical on you, we can start with a few guidelines:

     First, decide how low you want the shrub to become and cut everything off that is higher than, say, six feet. Then trim off  the sides where they hang over the sidewalk or run into other plants. This is your "butcher's cut." Or, if you want to be more artsy, it is the first block cut of a sculptor -- who may see a masterpiece within, but the rest of us just see a rough cube of stone. The practical thing here is that you have removed enough to see how the plant has been growing and what you will need to do.

     Second, start second and third cuts. As a rough way to start, make your second cuts 6" lower than your block cut and your third cut 12" lower. You end up with a shrub that has one third of its branches at three different levels. And you have punctured that dense shell at the top that prevents sun from reaching lower leaves.

     Third, with your second cut I hope you will start noticing how your plant grows. It is time to start looking seriously at what you are doing. Many shrubs, for example, tend to send up 4-5 branchlets where they were cut before. Some shrubs, like burning bushes and many viburnums, have enlarged nodes from which these branchlets protrude. So alter the 6", 12" scheme to fit the node. Make one of your cuts a cut that cuts below these nodes. Instant thinning. It does not matter where it is the first, second, or third cut, as long as you get the size you want.

     Now for the more mystical part.The 0, 6,12 rule and the cut below the node rule are just a rough start. Part of what they do is get you close enough to your plant to begin to understand it. As you are snipping you should also be looking at how it has grown. To the extent you understand the growth, you can begin to intervene in a way that helps the plant do what it wants to do, rather than imposing your will on it.

     The key thing here is to look at how branches form and how buds grow. Your general rules need to be modified to cut, where possible, to an already existing branch. If that is not possible, go for a bud. But not any bud. Look for one that seem to be going in the direction you want  - not straight up, not straight down, not back to the center, but angled in the direction you hope it will go.

     If this all sounds a bit intimidating, I apologize. Gardening is supposed to be relaxing, right? So do the 1/4 thinning from the ground first and follow the 0,6,12 rule. That is enough for the first year. Next year you can look at the results and come up with a more sophisticated approach. And if you make a mistake, don't worry about it. Plants face far worse enemies than you and they will survive your errors. And eventually they will be glad you are around.

     One of my favorite clients told me that pruning is now one of her best therapies for purging the frustrations of a trying day. Soon you will be able to join her.


Monday, April 2, 2012

Thinning Shrubs vs. Shearing

Many experts advocate removing 1/3 of the stems. I will jump for joy if you remove 1/4.

     Those who have been using hedge clippers for a number of years may have noticed something: no matter what you do, your shrubs keep getting larger. And while the outer shell stays nice and green, there is less and less below and inside. This is a result of unrelieved shearing without thinning.

     When you cut off the end of a branch most plants will grow two or more new tips to replace the old one, and the leaves become more dense. Within limits this is a good thing -- especially in shady areas where plants tend to open up.

     But repeated shearings make the outer shell too dense. The leaves on the top and sides block sun and air from the interior and the branches there die back. The effect is even worse when you have pruned in the notorious "W" shape that I mentioned earlier. Now you have an overhang that cuts even more sun from the plant's lower limbs.

     Even in formal gardens regular shearing needs to supplemented with thinning to allow sun and air to get to the interior of the plant.

     And here we come to my Number One Pruning Rule for multi-stemmed shrubs. It is simple, it is easy, and almost no one does it. Every spring you should cut up to 25% of your stems to the ground. If this sounds too scary, cut down one or two this year. When you notice in July that you can't tell the difference, you will be bolder next spring.

     You should go after the largest, oldest stems first, then stems that are going in a direction you do not like or ones that cross through the plant and rub against other branches. By doing this you accomplish four things:

     1. You open up the plant to more air and sun.

     2. You improve the shape of the plant by getting rid of stray and crossing stems.

     3. You rejuvenate the plant as old weary stems are replaced by new ones.

     4. You help control the plant's size because the oldest stems are the tallest and thickest and the most difficult to trim at the top. 

     I'll talk about pruning the the upper parts of shrubs next time.