During the hot months, perennials fill bloom gap

By Adrian Higgins

The Washington Post

Plant forms create structure in a garden, and leaf ornament brings texture, but let’s face it, flowers provide the greatest thrill. I’m thinking of this now as gardens generally are in the floral wasteland of July and August.

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Adrian Higgins, Washington Post A variety of the hardy ice plant flowers well into August.

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The truth is, you have to work at filling this gap to keep the garden from looking washed out and tired by the heat. Annuals bridge the dog days, along with the tropicals that are so popular today, but there’s a raft of perennials that provide weeks of show as the days begin to shorten.

There are some obvious candidates, all of which I can see from my porch. The stand of purple coneflowers is high from the spring rains and in full color. In a month the seed heads will be black and ripe and draw a resident tribe of chattering goldfinches. Coneflower breeders have been hard at work to bring about fresh varieties, some more enduring and worthy than others. University of Georgia horticulture professor Allan Armitage describes 47 hybrids in his book “Herbaceous Perennial Plants.” More are being introduced, and the color range includes clear reds, golden yellows, wine purples and white. ‘Pink Double Delight’ has dazzling pompom flowers on 24-inch stems. Its white counterpart is ‘Coconut Lime,’ named for its green-tinted creamy blooms.

One daisy plant worth getting to know is the Mexican hat, or ratibida, named because the central disk rises so high that the dainty bloom looks like a sombrero. Most are yellow, but a variety named ‘Pulcherrima’ has beautiful mahogany-red petals.

A friend raves about a recently introduced variety of blanket flower, gaillardia ‘Oranges and Lemons.’ Its flowers are a muted blend of orange and yellow and, to my eye, far more pleasing than the clunky red and yellow of traditional varieties. It started to bloom in late spring and will keep going until frost.

Butterfly weed, Asclepias tuberosa, has already begun to show its clusters of orange blooms and is drawing monarch butterflies. I saw it paired daringly but effectively with the magenta-flowered poppy mallow or winecup (Callirhoe involucrata). The flowers are held aloft from the low-growing foliage, and it blooms for weeks in hot, sunny locations. It deserves to be used more than it is.

All these plants require a sunny site and, most of all, well-drained soil. They won’t thrive in sodden heavy clay.

The hardy ice plant is a mat-forming succulent with spring and summer blooming species that produce a carpet of daisies in vivid colors. Delosperma cooperi began blooming a violet-pink in June and will flower well into August. It insists upon excellent drainage and would be good for a poor, dry site that has been amended with gravel.

If your soil is poorly drained, add lots of organic matter and then put in some summer perennials that will take moister soil. Physostegia virginiana is a particularly long-flowering summer perennial. The white variety ‘Alba’ has begun to bloom. Pink forms flower a bit later and last into early fall.

All these plants need a lot of sunlight. What about shadier gardens? Shade gardens are more about leaf textures and associations than flowers, but many hosta varieties are effective summer bloomers. Varieties of Hosta plantaginea often have a bonus of being fragrant. Two classic varieties are ‘Royal Standard’ and ‘Honeybells.’

A far less familiar shade perennial is the palmate umbrella plant, which has lovely cutleaf foliage and a flower stalk rising two feet or more bearing clusters of pinkish or white fuzzy flowers. Its botanic name, if you want to track it down, is Syneilesis palmata. It is one of those novel plants that remind you that the garden offers endless possibilities, no matter the season.