Midsummer often finds gardeners searching for a steadfast bloomer to fill empty spots in a floral border. Surprisingly, an old stand-by, yarrow (Achillea), may be just the answer. Oh, you say? You've tried that but didn't like their weak stems falling over on top of rampantly spreading foliage mats?
If you've had that disappointment, try again, this time with one of the newer hybrids known for shorter, stouter stems and slower growth, far superior in nearly every way to older species, common yarrow (A. millefolium) and fernleaf yarrow (A. filipendulina).
Older yarrows flop. Their ground-hugging foliage spreads without restraint, crowding out neighbors. Weak stems up to 3 feet tall or higher require staking to prevent their tumbling to the ground.
While some of us ignored yarrows altogether, hybridizers were busy crossing and back-crossing selected forms, some for sturdy stems, others for color, still others for size. The newer hybrids — known by their group and/or cultivar names — develop flat or slight dome-shaped flower clusters on shorter and often branched stems and retain their fernlike lacy foliage and pungent scent.
One group, the Galaxy Series, boasts strong stems and festive colors that add both hot sizzle and bright pastels to floral borders, though they may fade in severe heat spells after an intense first bloom. To use as fresh cut or dried flowers, cut stems while colors are vibrant.
Salmon Beauty may be the best known of the series. Flower stems attain 1- 2 foot height with broad, flat heads in muted shades of salmon pink that fade to buff. Blossoms repeat when stems are deadheaded throughout summer.
Great Expectations flowers in primrose yellow on 2-foot stems. Appleblossom, a little taller, blooms in bright peachy pink. Heidi, pale to deep pink, begins bloom a bit later than others. The Beacon, intense rose-red with spots of yellow at the center of each tiny floret, outshines them all.
Some hybrid groups come only in a mix of colors. The Debutantes, which develop large flowerheads on 18-inch stems, include pinks and reds, lilac, orange, gold, and cream.
The Summer Pastels, which can be grown from seed (available from Thompson & Morgan, www.tmseeds.com) also bloom in an unpredictable array of apricot, salmon, scarlet, lilac, cream, orange, white and gold on 2-foot tall stems.
Old and new favorites
Among the older cultivars of common yarrow, many continue to be loved by gardeners and are widely grown despite the need for staking.
Selections such as Cerise Queen, Fire King, and Red Beauty remain popular red bloomers but may be too vigorous for most gardens, despite the appeal of their dark green, soft, ferny foliage.
Paprika, a newer cultivar nearly identical to The Beacon, bears large spicy red clusters marked with a tiny yellow center. During heat waves, it fades to pink, though more slowly in afternoon shade.
Moonshine, one of the most widely grown yarrows for its lemon yellow flowerheads and 18- to 24-inch stems, tends to die out after a few years. It rivals taller Coronation Gold both in the garden and as a cut flower.
Most nurseries carry older types as well as the newer hybrids. When purchasing yarrows, check tags to determine stem height and overall vigor. You'll find a wide selection at Digging Dog Nursery up the coast in Albion (diggingdog.com) and also at Emerisa Nursery in Santa Rosa.
Several years ago, I purchased Achillea serbica from highcountrygardens.com as an edging along rocks where there's minimal irrigation. Unlike most other yarrows, this species bears short linear, grayish green foliage with a silvery cast in little 4 x 8 inch tufts. Buff flowers rise in early summer on short, wiry stems.
This tough little plant roots easily from cuttings and has proved longer living in my garden than other low-growing yarrows, Achillea x kellereri and A. x lewisii King Edward.
These latter species have fernlike foliage in clumps from 4 to 8 inches tall and wide. Both bloom in buff to yellow, though King Edward flowers are brighter.
Easy, easy, easy
Yarrows grown in rich rather than poor soil tend to spread fast and produce weak stems but may need amended soil to improve drainage. Give them regular irrigation until they are fully established and able to withstand periods of drought.
Wide clumps of blooming yarrows become butterfly magnets. Their broad, compact flowerheads composed of hundreds of tiny florets also attract beneficial insects.
Because of a willingness to spread quickly, it's possible to use older forms of common yarrow foliage as a small-scale lawn substitute, which means mowing in summer with a loss of flowering. If you try it, choose forms with a groundhugging habit. Plants spaced at 2-foot intervals will touch within one year.
Rosemary McCreary, a Sonoma County gardener, gardening teacher and author, writes the weekly Homegrown column for The Press Democrat. Write to her at P.O. Box 910, Santa Rosa, 95402; or send fax to 664-9476.