Stars of the shade: Hydrangeas - includes related article on growing and pruning hydrangeas

Sunset, May, 1999 by Lauren Bonar Swezey

Few shrubs can compete with hydrangeas' dramatic show of summer flowers - especially when you're dealing with shade. In addition to the familiar blue, red, pink, and white globular flower clusters of garden hydrangea (H. macrophylla), there are unusual species with strikingly different flowers and foliage.

Some develop huge flower heads, while others are more delicate. Leaves may be narrow or lobed, hairy or glossy.

The six we've chosen represent the range of choices. All grow well from the Pacific Northwest to coastal Southern California. Several are hardy in the coldest climates. Those listed here grow 4 to 6 feet tall except as noted. For planting and care tips, see page 87.

H. arborescens 'Annabelle' (also sold as H. arboreum 'Annabelle'). Huge white globes cover the plant all summer. Withstands some drought; grows in shade or sun. Hardy to -30 [degrees].

H. aspera, H. robusta, H. sargentiana. These have lavender-blue or white lace cap flowers and hairy, pointed leaves. The form sold as H.a. villosa has a spreading habit. H. robusta and H. sargentiana grow 9 to 12 feet tall. Prune hard if plants get leggy. Hardy to 0 [degrees] (-10 [degrees] if protected).

H. macrophylla. This large category of familiar plants includes mopheads (large, round heads) and lace cap hydrangeas (flat heads with small, star-petaled flowers surrounded by large showy flowers). H.m. 'Ayesha' has small, waxy pink flowers several times thicker than those on other H. macrophylla varieties. Hardy to 0 [degrees] (-10 [degrees] if protected).

H. quercifolia (oakleaf hydrangea). Long-lasting flowers in conical clusters turn from white to pale pink. 'Snow Flake' has double flowers. 'Snow Queen' has 12-inch-long flowers. Bronze or crimson fall foliage. Hardy to -30 [degrees].

WHERE TO BUY PLANTS

The following mail-order sources carry many unusual kinds.

Forestfarm, 990 Tetherow Rd., Williams, OR 97544; (541) 846-7269. Catalog $4. Sells 46 kinds.

Gossler Farms Nursery, 1200 Weaver Rd., Springfield, OR 97478; (541) 746-3922. Catalog $2. Sells 30 kinds (accepts orders September through April 15).

Greer Gardens, 1280 Goodpasture Island Rd., Eugene, OR 97401; (800) 548-0111. Catalog $3. Sells 45 kinds.

Heronswood Nursery, 7530 N.E. 288th St., Kingston, WA 98346; (360) 297-4172. Catalog $5. Sells 75 kinds.

Hydrangea Plus, Box 389, Aurora, OR 97002; (503) 651-2887. Catalog $4.50. Sells 74 kinds.

Hydrangea basics

Growing. Hydrangeas tolerate full sun near the coast; inland, give them partial shade. Plant them in rich, porous soil (lighten heavy clay soils by mixing in plenty of compost or peat moss). Hydrangeas prefer moist soil, but established plants can get by on less water in coastal areas. Plants are especially beautiful when massed in large beds, or planted singly in pots.

Pruning. To control size and shape, prune plants after flowering. Cut out stems that have flowered, leaving those that have not. For big flower clusters, reduce the number of stems. For numerous medium-size clusters, keep more stems.

Changing the flower color. In acid soils, pink and red garden hydrangeas often turn blue or purple. To make (or keep) flower color blue, apply aluminum sulfate (1/4 ounce to 1 gallon of water) to the soil several times in spring and fall, at weekly intervals. To keep flowers red or make them redder, add lime to the soil (apply 1/2 pound to every 5 feet of surface area under branches once or twice a year.