If you are like many of us and have aspens planted in your Colorado yard, you know that eventually you have to deal with the annoying problem of suckers. While aspens and poplars are notorious for throwing suckers, you’ll also find them popping up around many other trees. Trees like apples, crabapples, cherries, nectarines, pears and peaches will all send suckers shooting up in the area in which they are planted. It doesn’t matter either whether the tree is ornamental such as a crabapple, or an edible apple, these particular varieties will produce suckers.
True suckers are the sprouts that come up around the tree you have already planted and grow from the roots which run underground. If they become well established and are happy, it seems like there is no end to how far they can spread. We planted aspens in our yard twenty years ago and have found them in the lawn as far as 50 feet away from the original tree.
Suckers are not to be confused with seedlings. Elms, for instance, won’t sucker, but are widely known for re-seeding like crazy. Although on the surface, the shoots coming up appear to be the same, in fact, they are not and should be treated differently.
You have a couple of choices when deciding how to deal with your sucker problem. The easiest way is to simply cut them off either by hand or when mowing. While this quickly eliminates the unsightly sucker from your yard or garden, it isn’t always the best way to deal with them. Cutting suckers like this acts in the same way that pruning does. Since pruning is often done to encourage branching, this can simply produce more suckers off of that main root. Since you are cutting the sucker off at ground level, you have no idea where the root is underground and how favorable the conditions are for continued branching.
You can also try to pull them off. Aspens will detach fairly easily, but there are other trees which are tougher and you’ll have a difficult time getting them to break off cleanly.
Many people think that spraying them is the answer and most people think of Roundup or another glyphosate preparation. I would advise against using this method. Even though it will most certainly kill the suckers, the chemical can, and often does, translocate the poison through the system of the plant to the main tree and can kill the tree.
The product we like best as a control for suckers is called Sucker Punch. This is a topical formula that you paint onto the leaves of the sucker. It is very effective in killing them but will not hurt your main plant. Like most things, it works best if you get after them early and use it when they are still small. If your talent does not lie in painting, no worries. You don’t have to cover every leaf and it will be rainfast within a few hours if your plant is in an area where there are sprinklers. As with any chemical control, follow label directions carefully.
All of this being said, there is some hope in eliminating the problem of suckers down the road if you are just starting to plant. Many trees, fruit trees in particular, are beginning to be grafted onto root stocks that won’t throw suckers. These are called “right root” and it is a patented system. If you are looking to plant aspens or anything else in the poplar family, these trees are grown from seed and cannot be grafted, so you will be forced to deal with suckers on them.
If you hate those little suckers as much as we do, get after them early on before they have time to spread, unless your goal is to have a naturalized forest in your yard.