Stress escalates in the late summer for both gardens and gardeners. Even if you live in a climate that luxuriates in cool nights, the days are long and often dry. The best plan is to join forces with the season rather than fighting it. Having plenty of colour in a late summer garden calls for advance planning, especially if your garden is built around bulbs and perennials. Here are some tips for choosing care-free flowers that don't take too much work.
Planning your garden
- Although daylilies, monkshood, rudbeckia, and several other perennials provide bright mid- to late-season blooms in cooler gardens, in hotter areas, colourful plants for late summer are more limited.
- Look for heat-tolerant annuals, succulent perennials, those perennials that are native to hot, arid climates, and the few late-blooming shrubs that are available in nurseries.
- When you plant magic lilies, you'll see flowers appear within days of a deep, soaking rain in mid- to late-summer.
- In general, however, late summer is often a lull time in gardens. Summer's perennials are past their flowering peak. Some long-performing annuals that you would think you could count on, such as marigolds, temporarily cease flowering during heat waves.
- Fall-blooming asters, chrysanthemums, and goldenrods are waiting in the wings, ready to respond to the shorter days of autumn.
- The best way to bridge the flowering gap is to fill the gaps in your garden with long-blooming, heat-tolerant annuals.
Some like it hot
- Although they can succumb to the barest hint of frost, plants that have tropical origins are custom-made for the sultry season.
- Plants from hot climates, such as lantana, canna, caladium, tithonia, and sweet potato vine, grow rapidly and flower abundantly in the heat that causes other plants to wilt and stop flowering. In warm climates, these and other tender perennials are routinely grown in the ground year-round.
- In Canada's cold-winter climate, tropical plants are treated as annuals, or dug up at the end of the season and overwintered indoors.
- Grown in sunny beds of moist soil, or in pots of moist soil, caladiums will light up any shady or partially sunny place, and the cascading stems and chartreuse or deep purple leaves of sweet potato vine is the finishing touch for a container garden composed of several species of summer-flowering annuals.
- To derive maximum performance from tropicals, be sure to water them often enough to keep the soil slightly moist during their summer growth period. Fertilize them with every other watering, using a balanced, water-soluble fertilizer mixed at half strength, according to the package label.
- Several popular bedding plants are tropicals, too, including impatiens and annual geraniums. Indulged with an extra ration of care, these heat-tolerant plants can pull your garden through the hottest season.
- Heat-tolerant annuals, such as cockscombs, sulfur cosmos, and zinnias can provide a rainbow of late-summer colour, and gomphrenas are always willing to produce colourful papery flower bracts in the hottest weather.
- In sun or partial shade, annual salvias will respond to fertilizer and supplemental water by sending up a fresh flush of flower spikes.
- Nearly all annuals planted in spring, whether in beds or in containers, will be in need of a little pampering by late summer.
- Spend a little extra time with your annuals, pinching off spent blossoms and old stems, and giving them all a deep drench with a water-soluble, balanced fertilizer. The results can be dramatic, including improved leaf colour within two days, and a fresh flush of flowers two to three weeks later.