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Deadheading key to a continuous bloom

Watering in dry spells also important

This week I answer a question about perennials.

Q. I am new to the West Coast. My new home has a potential flower garden that is two feet deep and around 20 feet long and faces south. So far I have planted one blueberry bush and a few daffodil bulbs. I work long hours so by the time I get the laundry, cleaning and groceries done, it's time to go back to work. What sort of perennials are hardy and slug resistant yet bloom most of the summer with minimal maintenance?

A. There are perennials that flower almost all summer with very little maintenance. Watering in dry spells is essential for some, but the real key to continuous bloom is regular deadheading. Once a plant sets seed, its life purpose is fulfilled, so it doesn't need to keep on flowering.

If you never deadheaded, plants may change their usual long flowering periods into short ones. If you deadhead several weeks late, plants may try to flower again, but it takes time to form buds, so you'll get intermittent flushes of bloom.

One of the blue-flowered cranesbills (botanically Geranium Rosanne) is reputed not to need deadheading at all. It has beautiful, prolific blooms, is dwarf and easy to obtain.

Meconopsis cambrica, is unusual among perennial poppies because it produces its yellow (sometimes orange) flowers all summer and into frost season with very little deadheading. But deadhead anyway. Its seedheads spawn endless progeny and those long taproots are impossible to remove. So pretty/so reliable/so invasive! The daisy family tends to be long-flowering. One of the longest and brightest sequences is the yellow, brown and orange mixes of Gaillardia (often combined in each flower). Echinacea is another long-blooming daisy available in pinks, white, orange and yellow.

Rudbeckia contains many species of bright yellow cone-flowers that bloom from July to frost. Heights range from about six feet (two metres) to just over one foot (30 cm). Knautia produces blood-red scabious blooms (there are pastel forms) all summer. It's compact in poor soil, an untidy sprawler in rich conditions.

The alliums (flowering onions) leave behind longstanding flower heads. Two of the more spectacular are Allium christophii and Allium schubertii.

Globe Thistles (Echinops species) have blue globes spectacular long after the flowers fade. Sea Hollies Eryngium planum, for instance, has purple flowers, prominent calyxes (like a saucer under a purple cone) with metallic purple stems.

Some roses are most reliable. The Flower Carpet series flowers from late spring into late fall (with deadheading).

There's a large colour range in this series and it's very dwarf, though it spreads widely. Garden centres offer many other landscape roses, virtually all long-flowering though mostly non-fragrant.

Technically Sweet Alyssum is an annual, but it covers itself with flowers (purple or white) all summer, is fragrant and seeds itself thickly year after year. It's very short and never needs deadheading (you wouldn't want to anyway because it's too fiddly).

About deadheading: it's easier if the pruners can be hidden somewhere between your gate and your front door. Regular deadheading soon becomes a brief routine. It's clean work and only a few snips each time.

If you deadhead spent flowers before seedheads form, you don't need to pick up the remains at once. Call it mulch and get it when you can.

Anne Marrison is happy to answer garden questions. Send them to her via amarrison@shaw.ca.