Sunday 22 September 2019

Get suckers under control

What's the difference between a sucker and a shoot?

SPRING GROWTH: It is time to check the garden for unwanted suckers
SPRING GROWTH: It is time to check the garden for unwanted suckers

Gerry Daly

How are our trees and shrubs cultivated? Some garden plants are grafted with the top cultivated part, which usually has good flowers or fruit, grafted on to a wild or more vigorous root system in order to boost the growth of the top part. This is done with a lot of trees and shrubs, such as roses, lilac, flowering cherries, contorted hazel and viburnum.

A sucker is a shoot that comes from the base, or the roots of the plant rather than from the top. A sucker growing from the top is fine and doesn't need attention.

However, when they grow from the root stock, it means the root stock is trying to take over and grow using its own top-shoots.

Plants that are grafted always want to produce their own suckers - 'suckers' because they take from the roots of the plant.

And the plant wants that to happen because it wants to spread.

Sometimes suckers appear quite a distance from the original parent tree. For example, American aspen, which is related to poplar and has those rustling leaves and a lovely golden yellow in autumn, is a notorious suckering tree and can appear as much as 40m from the parent tree.

So this is a way that tree species spread in suitable ground, very much as they would if they were producing seeds.

Stag's horns sumach is a common small tree that sends up suckers, maybe three or four metres away from the parent tree with the same objective of producing a thicket of trees. You don't necessarily want that to happen in the garden, although it can be very decorative.

Most cottage garden plants, like sumach, are easy to propagate, and they get passed on readily. Clerodendrum or glory bower tree is very beautiful with little white flowers and lovely gold and purple shades.

But it has plenty of suckers, sometimes two or three metres beyond the five-metre canopy. It is such an excellent plant, it is well worth the extra effort of having to control a few suckers.

Lots of flowering cherry trees, grafted or not, throw up suckers. Sometimes cherries that are growing as a street tree come up in neighbouring gardens.

Robinia is very like an ash with its divided foliage and white flowers in the early part of the summer and it is a superb garden tree, but can send up suckers 20m from the parent tree. Suckers can come up in shrubs and flowers, and they can be awkward to get rid of. And the key is to tackle them in one or other of two times a year.

Now, in spring time, is one key time before they get the burst of growth that makes them more difficult to control.

Otherwise, wait until midsummer when the new growth has come on and they're soft and easily taken out.

Use a spade and chop them off at the root. Clear a little ground about a foot square or around the shoots, which normally don't extend much below 10cm under the soil, as they need oxygen. Drive the spade down hard into the ground, cutting the root and pull the root out of the ground.

Replace the soil and stamp it down very hard with your heel so that there's not much oxygen or air getting down into the soil.

Very often, suckers appear in the same place again because oxygen is a trigger for sucker growth. It is time to take a stroll around the garden and get those suckers under control.

Spring in your step

Now that spring is approaching, it's time to explore some of the country's garden treasures. Hillsborough Castle and Gardens in Co Down opens its doors daily for the first time on April 18. Check out the Lost Garden, Moss Walk and Parterre Garden, all of which have been meticulously restored, while the lovely Walled Garden will inspire many a grower - it produces produce for the new visitor's cafe. For more, see

Old beauties

Magnolias are ahead of the season this year and look fantastic with a great show of splendid flowers, glistening white or wine-stained and shaped like large tulips. Last year's hot summer suited these plants that hail from a climate of high light and heat, Magnolia is a very ancient genus, at least 20, possibly 100m years old, one of the oldest of flowering plants, preceding conifers.

Green and tasty

As any gardener knows, get your kids growing veg and they are more likely to eat their greens. Incredible Edibles, now in its 11th year, kicks off the season helping over 1,500 primary schools make the journey from farm-to-fork with a free kit that contains handy tools for a school garden from compost to seed potatoes. For more, visit

Sunday Independent

Editors Choice

Also in Life