A three-year proposal to solve Judy's lilac situation

Each week, Susan Richards of New North Greenhouses answers your gardening questions. Have questions about your gardening needs? Please email her at [email protected]

Two questions from Judy:

1.We have an apple tree that was there when we bought our house. It is very tall and only gives apples every 2nd year. The leaves are always spotted with black and the apples tend to be more 'rotten' than good.

While it's a lovely tree I am not sure if it's better to just cut it completely down or somehow 'trim' it with hopes of it producing better and more consistent fruit. I have no 'green' thumb so would appreciate your take on this.

It's perfectly normal for some apple varieties to produce every second year. You won't be able to change that.

The disease you are describing sounds like apple scab, which can affect both foliage and leaves.

The tree can be sprayed early spring while dormant with a combination of lime sulphur and dormant oil. The lime kills over-wintering disease spores and the oil smothers insect eggs. You are too late for the oil now but can still apply the lime sulphur throughout the growing season.

You can also spray a fungicide containing copper sulfate to help control disease. Just remember that no spraying should be done when the tree is blooming. This is when bees are pollinating flowers!

As to pruning, opening up the crown a bit to allow more light and air flow will help fruit formation.

I have very tall lilac trees and I would really love to be able to harvest the blooms and enjoy them but could never reach them. Is it possible to cut down the height of this lilac tree to a more manageable height? This would only leave a trunk — will shoots grow again? 

The best method to rejuvenate an old, tall shrub is to look carefully at the structure and make a three-year plan. If it has 12 main branches emerging from the soil, plan to remove 4 this season right down to the ground, and shorten the remaining branches by 1/3 of the current growth length AFTER the lilac blooms.

Next spring, remove 4 more main branches down to ground level and prune again as above.

Year 3 you will cut down the final 4 main branches and prune again after flowering. You now should have a healthier, shorter lilac shrub.

Chris: I'm struggling to get grass to grow under the shade of a mature maple tree. I've reseeded several times with grass seed mix for shady areas. What am I doing wrong?

If the correct seed mix is unsuccessful despite following instructions for seeding then there just isn't enough light for grass to grow.

Here are a few alternatives;

With careful pruning, you can thin the tree canopy to let more light in.

Or,

Remove all poor grass and put down landscape fabric and mulch to keep the area tidy. For a pop of colour you can add pots of shade loving annuals to the area.