Get the last of the nursery stock acquired in April and May into the ground - now. Wait until direct sun has left the site and be generous with water for the rest of summer.
Stake lilies. The stake should be as tall as the lily stalk will eventually become; tie stem loosely to stake as close to the top as possible. Staking a lily only to the midpoint is an invitation to a broken stalk. One-inch-wide strips of cloth are the gentlest ties.
Plant tender summer bulbs (caladiums, dahlias, etc.). For strong dahlias, dig holes a foot deep; set tubers in and cover only partly with soil. As the shoots grow, gradually add soil to the hole, always leaving the tops exposed; when the shoots are 3 inches above ground level, the holes can be completely filled. This presumes excellently drained soil, or the dahlias will drown.
Continue sowing a few green beans at a time to allow continuous harvests later.
Last chance to plant these vegetables: limas, cucumbers, eggplant, squash, and pumpkins.
Sow chervil and cilantro repeatedly all summer to compensate for their tendency to bolt fast (produce flowers). Sow more quick-growing annuals like cosmos and nasturtium.
Put cages or stakes around tomatoes, even if the plants are dinky. You'll be glad later.
Prune early-blooming clematis, such as C. montana, if desired to reduce the size. By pruning now, the subsequent new growth will have time to mature before winter and bloom next spring.
Prune azaleas and rhododendrons (except late bloomers), mountain laurel, pieris (andromeda). If you have vast plants, you can be radical. There is some risk in cutting an old plant to stubs, but most will sprout because the roots desperately want some leaves doing the photosynthesis thing. As a compromise, cut back a third of the plant. Beware: They may look like Addams Family oddities for a couple of years. As with early clematis, do this now or not at all.
Mulch, always understanding the principal purpose: moisture retention and cooler soil. Weed suppression (not weed elimination) is a bonus. A 2-inch layer is enough; more is not better. "Volcanoes" of mulch around young trees are counterproductive; mulch (or soil) should never go above the flare of trunk, where it widens into a root system. Best for trees is a wide saucer with a rim, thus capturing rain instead of shedding it.
Leave foliage of daffodils and other bulbs to mature naturally - the bulbs need the continued photosynthesis. Braiding or rubber-banding the foliage significantly reduces the amount of photosynthesis. (If the leaves are too untidy for you, bend them to lie flat on the ground all in one direction; they'll double as a temporary mulch.)
If chrysanthemums and asters have grown enough since the last pinching, do it again. There should be at least two, preferably three, nodes (junctures on the stem from which new side shoots will emerge) remaining after pinching.
Keep the lawn mower on a high setting. Cutting long grass too short runs the risk of "sunburn."
Keep the compost cooking, not stinking. All the green matter (grass clippings, celery trimming, corn shucks) needs dry material if it's not to get rank. If you don't have dry tree leaves from last fall in some corner, leave a mowing of grass on the lawn. Allow it to dry fully, then rake up and mix in. Or spread the clippings on the driveway to dry. If desperate, buy a bale of straw (not hay, full of seeds) and mix into the compost, or use some noncompacted output of a paper shredder (avoid slick paper with lots of color ink). In all cases, the dry matter must be mixed in with the green.
- Michael Martin Mills