When to prune? It depends on the plant

10/7/2009

One of my favorite garden tools is my small pruner. It fits so nicely in the palm of my hand. It glides together smoothly, then pops back out, ready for another task. I feel so powerful when I have it tucked in my back pocket, even if I don't always need to pull it out to snip a stray branch out of the way.

But just like any other tool in the shed, you have to know what you are doing with it. After basic pruning to get rid of disease and broken limbs, the rest of the process generally happens after a plant has flowered. If the shrub flowers in the spring, leave it alone right now. It is setting its blossoms for warmer weather. Because they flower at different times of the year, you are pruning something just about every month of the year. I get a lot of letters asking when different woody shrubs can be trimmed. Here are a few of the top species you have asked about:

• Barberry. Also known as Berberis, this dark-plum shrub has a rich color and looks great with lime green foliage of spirea or hosta. But look out! It has a lot of sharp spikes. This makes a great choice to plant under your windows or on the property line as a safety feature in your landscape.

Put this one on your pruning calendar to reshape in early summer. The plant starts to flush out its new shoots in the late summer. It will be a good time to prune out the dead branches, always cutting back to a healthy part of the stem. Because it has sharp spikes, be sure to use gloves when you reach in there to prune. Cut the tips back by two-thirds so they will keep pushing more shoots out from the base of the plant. They are putting on their fall berries right now, so let them go for the winter.

• Butterfly Bush. I could wallpaper my living room with the number of letters I receive asking about Buddleja davidii. This beauty needs to be pruned in early to mid-spring just after Jack Frost is done for the season. It might seem crazy, but you should cut all of the branches down, leaving just a few shoots on the stem. In many cases, the plant will be about six inches above the soil line. Don't worry because it will grow vigorously over the summer.

If your butterfly bush hasn't been pruned in many years, it will show the signs of weakness. Lots of thin arching stems and spindly flowers are typical of an ignored Buddleja. Cut it down to its original stem and you will see it flush again later in the summer.

•Redtwig dogwood. This shrub really shows off in the fall and winter, so don't do a lot of pruning just yet. Cornus alba 'Sibirica' sprouts lots of green leaves through the summer, then drops the leaves to show off its bright red stems in the winter.

Prune out the old wood to coax new shoots around the base. Snip off the new growth at the ends in the early spring to keep its framework uniform.

•Cotoneaster. I had a very sad cotoneaster in my side garden when we first moved into our house. My husband said, "Want me to pull that dead thing out for you?" How sweet! But instead, I pruned it almost to the ground and it has thrived ever since. Prune regularly in the winter. Get rid of anything that isn't producing foliage or fruit. If they are bare at the base, cut those stems a couple of inches from the ground. Snip off overcrowded branches to help the plant flourish. This year, my plant looks better, but still needs a couple more seasons of tending before it will be full again.

Just like the rest of us.