HARDINESS: Zones 4 to 9
PREFERRED SOIL pH: Neutral to slightly acid
PREFERRED SOIL TYPE: Fertile, well-drained
PREFERRED LIGHT: Sun
ATTRIBUTES: Tall flower spikes in a range of colors; for back of border, as specimens
SEASON OF INTEREST: Late spring to midsummer
FAVORITES: 'Old Barnyard Mix', 'Country Romance Mix'
QUIRKS: Plants are generally short-lived but easy to grow from seed
GOOD NEIGHBORS: Catmint, cleome, coreopsis, daylily, ornamental grasses, yarrow, zinnia
WHERE IT GROWS BEST: Sun, fertile soil in a wide range of climates
POTENTIAL PROBLEMS: Spider mites, Japanese beetles; fungal leaf disease rust
RENEWING PLANTS: Usually lasts 3-5 years; start new seeds to replace older plants
CRITTER RESISTANCE: Good except for deer
DIMENSIONS: Flower spikes to 5 ft (1.5 m) tall, plants to 2 ft (0.6 m) wide
Hollyhock in the Landscape
Hollyhocks are legendary among perennials, famed for their 5 ft (1.5 m) height, 4 in (10.2 cm) wide flowers, and broad color range. But the main reason hollyhocks have endured is their easy-to-please nature. These are survivors that return season after season for enthusiastic encores.
Place hollyhocks anywhere you need a strong vertical statement. With their tall upright stance, impressively sized rounded leaves and dramatic flower spikes, hollyhocks are unsurpassed as backgrounds in a flower border, for enhancing a wall or fence, or for sidling up to an arbor or gate.
A Rainbow of Hollyhocks
The flowers open from bottom to top, and it's always suspenseful to see what colors appear. Most hollyhocks are available as mixes, such as 'Old Barnyard Mix' and 'Country Romance'. Double hollyhocks are often sold in single colors, making it easy to capitalize on their more formal demeanor.
Set out seedlings in spring or early fall, in soil fortified with compost or rotted manure and in sun. Set plants 2 ft (0.6 m) apart and group them in trios. Water during dry weather to prevent wilting and fertilize twice during die growing season with a balanced fertilizer applied per package directions. In late spring, stake flower spikes to 6 ft (1.8 m) poles to keep them from blowing over in wind, a crucial step when growing the big double-flowered varieties.
Cut off the spires after the flowers are spent. Sometimes plants re-bloom on new, shorter spikes. Leave some old flowers at the bottom to ripen a new batch of seeds. Gather and plant the seeds after they turn black in fall, or store them in an envelope and plant them outdoors in spring.
Where summers are long and hot, you may get best results growing certain varieties as biennials, which are sown in fall for flowering the next spring and are not expected to return thereafter. However, given a chance, hollyhocks will persist as a perennial.
A fungal disease called rust, which leaves orange powdery deposits on leaves, can be a problem. Fig hollyhock (Alcta ficifolia) shows good resistance. If problems arise with other varieties, remove and dispose of affected leaves. If minute, sap-sucking red spider mites make webs on leaf undersides, spray the foliage with a stream of water, or treat diem with insecticidal soap per label directions.
Japanese beetles may chew leaves and flowers. Handpick and dispose of them in the morning when the beetles are sluggish or apply a botanical, neem insecticide as directed. The beetles feed most in sun, so try growing hollyhocks in partial shade. If deer nibble plants, tuck a bar of deodorant soap into clumps to repel them or use commercial repellent as directed.