Feed weak or patchy lawns this month. If the lawn is even and you mow it quite enough already, leave well alone.
Long grass planted with daffodils can be mown down now and kept short for the rest of the summer.
Pruning and Training
Trim back aubrieta and helianthemums with shears, to keep the plants in a dense mat.
Dead-head roses, and continue to spray against pests and diseases if
necessary. Tidy up those roses which have only one season of bloom after
they have flowered.
Shear back the green wiry stems (last year's shoots) on brooms (Cytisus
scoparius, kewensis, etc.) to keep them dense and stable.
Lift and divide bearded irises after flowering. Replant only the fattest,
healthiest fans, with the rhizome just under the surface of the soil, facing
south. Shorten the leaves if necessary, to keep the offsets upright.
Give liquid fertiliser to plants which enjoy plenty to eat and drink. E.g.
clematis, young hedges in a hurry, developing topiary, etc. It is
especially helpful to climbers growing hard against a wall where the soil
will be dry.
Keep patio pots well watered, especially if they contain thirsty plants like
cannas. You may wish to stand the pots in a saucer so they get a longer
drink every time you water.
On a mild rainy day, houseplants dusty from a winter indoors can go outside
for a shower. Bring them in again before the sun shines, or they will
scorch. Watch that weak-stemmed species are not flattened by the
unaccustomed weight of raindrops.
Make sure nets over strawberries and raspberries are proof against the
birds. Peg down a few runners if you want some extra plants. Otherwise
Plant out seedling leeks in individual holes. Plant out pot-grown tomatoes,
courgettes, pumpkins and sweet corn.
Keep the hoe moving between rows of vegetables while the weeds are still
just seedlings. Choose a dry windy day for best results. A few pieces of
paving slab placed between the rows now will make hoeing and picking a
cleaner and easier operation all season.