June in the Garden

Sow a few annual flowers and some lettuce indoors for use as fillers and replacement plants in garden beds next month.

Water drought-sensitive plants well and then lay a moisture-retaining, mildew-preventing mulch layer around them. Damp peat mixed with compost is suitable for woodland and acid-loving plants such as rhododendron and azalea. Use compost alone or mixed with composted manure around summer phlox, lupin and delphinium.

Set house plants outdoors this month for a summer vacation. Most tropical plants will do best in a sheltered, lightly shaded site such as under a canopy of high tree branches.

For strong summer growth and another fine round of flowering next spring, deadhead lilacs. Then fertilize, and mulch around the plants with compost or composted manure.

When a delphinium has finished flowering, cut the stalk back to the first good-looking leaf below the faded spike. This dead heading prompts the production of more flowers, from side shoots along the stem.

As the weather warms, choose lightly or partly shaded areas where the soil is humus-rich and easy to keep moist for succession plantings of lettuce.

Remove faded flowers from spring-blooming rock garden perennials such as rock cress (Arabis), Aubretia, and basket-of-gold alyssum.

Wait until fruit trees thin their crops naturally in the "June drop" before thinning out the fruit yourself. Do a first summer pruning of the trees late in the month, shortening side shoots to one or two leaves beyond the swelling fruit.

When peony buds fail to develop and open into flowers, the problem can usually be traced to drought, a lack of potassium in the soil, shade, generally inadequate soil fertility, or too deep a planting. If the peony is a very old one, it may need digging and dividing -- best done in autumn.