The flush of spring growth is over now so you have missed the boat for heavy pruning of plants such as rhododendrons, camellias and conifers which only put on one or two flushes. Other plants which grow all summer can still be pruned and shaped and cleaned up because they will continue to put on new growth after pruning. This includes vireya rhododendrons (which keep flushing repeatedly pretty well all year) , roses, clematis, luculias and michelias.
Do not forget to prune cherry trees this month. We admit we have yet to do ours.
With the sun finally generating some summer heat, weeds pulled out of the soil and left on the garden will shrivel away to nothing in a matter of hours. However, remove any weeds with seed heads, even if they are not fully ripe. The sun can ripen these quickly and if you leave seeding weeds on the surface, they will just sow themselves into perpetuity. It pays to carry a bucket with you while you are weeding or to tuck seeding weeds under a paver or stone where they can’t grow again. The key to weeding is to hoe them out while freshly germinated. Summer weeds such as portulaca and summer grass, if allowed to get some size, can survive hoeing and even survive being turned upside down with roots facing the sun. These need to be removed altogether.
The next two weeks are your last opportunity for planting corn with a good chance of getting a harvest. Planted this late, corn can ripen and hold into the winter through to June.
It is getting close to the cut off point for planting winter vegetables such as carrot and parsnip from seed so do not delay. If you are using plants, you have longer.
Keep tomatoes sprayed with copper.
If you have caterpillar infestations in broccoli or cauliflower, talk to your local garden centre about what pyrethrum based treatments are available. Pyrethrum is the active ingredient in flyspray and was originally extracted from a daisy. These days it is more likely to be synthetic but it remains a pretty safe and acceptable control. Alternatively, if you don’t like added protein to your cooked vegetables (while Mark does not mind the odd cooked caterpillar, the rest of the family find it very offputting), you can sprinkle lots of salt over the florets as you prepare them, then cover them with cold water for a few minutes while the caterpillars die. Rinse them thoroughly, inspect closely and cook with no added salt.