How to Grow and Care for Hollyhocks? The Complete Guide

Hollyhocks (Alcea rosea), a traditional component of cottage gardens, blossom in the middle of the summer on towering spikes. The majority of the most popular types are biennials, which means they go through their whole life cycle in two years. The first year is dedicated to storing energy and producing leaves. The stalks extend higher in the second year, blooms open, and seeds begin to grow. However, there are also several types that, when planted early enough in the spring or started indoors in winter, act like short-lived perennials and bloom in their first year.

Hollyhocks don't need much maintenance, other than staking and trimming the stalks after flowering, but they do need to be guarded against pests and fungi that cause illnesses like rust. In addition to serving as a host plant for painted lady butterflies' caterpillars, hollyhocks also draw other pollinators like bees and hummingbirds. A cottage garden simply cannot be finished without a few hollyhocks around the perimeter.

Here's How and When to Plant Hollyhocks?

Hollyhocks can be readily planted from seed both inside and outdoors. A week or so before the final frost, seeds can be immediately planted outside. Sow the seeds just 1/4 inch deep and about 2 feet apart. Because of their lengthy taproots, hollyhocks should be started indoors in tall, separate pots and transplanted as soon as possible to prevent harm. 9 weeks before the final average frost date, start indoor seedlings. After the final frost, seedlings can be transplanted outside two to three weeks later. Remember that some plants are biennials and might not bloom until their second year.

Where to Plant Hollyhocks?

Plant in full sun to moderate shade in a well-draining environment. Because of their height, shield them from wind-related harm and offer support with a fence, wall, trellis, or stake. If left to their own devices, hollyhocks will quickly self-seed; thus, plant them in a location where this won't be an inconvenience. Hollyhocks are also among the few plants that can be grown close to black walnut trees because they can withstand the chemical juglone that the tree leaches into the soil.

Hollyhock Varieties to Grow:

Alcea ‘Rosea Nigra’ – deep maroon flowers from June to September. Reaches a height of 2m.

Alcea ‘Halo Mixed’ – a mix of white, purple, and pink single flowers held on 2m high stems. Flowers from June to July.

Alcea ‘Chater’s Double Icicle’ – a pure white double with flowers that resemble puff palls. Flowers from July to September. Reaches a height of 1.5m.

Alcea ‘Black Knight’ – nearly black, single flowers anytime from June to September. Reaches a height of 2m.

How to Care for Hollyhocks?

Pruning: Hollyhock stalks can be trimmed down to the root after flowering, and individual blooms can be taken off as they wilt. By doing this, seed heads won't develop and won't spread. However, you should leave the blossoms and a few stalks until the seeds have fallen if you want seeds to be planted for the next spring. To prevent the rust disease from overwintering, all stems and leaves should be cut back to the ground since they will die back in the winter.

Soil: Provide hollyhocks with rich, moist, and well-drained soil.

Fertilizer: Hollyhocks grow from a springtime application of compost or fertilizer.

Watering: To start hollyhocks, give them regular watering and keep the soil damp. They are quite drought-tolerant plants after they have established the roots themselves. Avoid soaking the foliage when you are watering; doing so might cause sick leaves.

Propagation: Hollyhocks rapidly self-seed if flower stems are left in situ and are best and simplest cultivated from seed.

Pests and diseases: They are susceptible to hollyhock rust, a fungus that starts as yellow spots on leaves before turning into brown or rust-colored pimples on the underside of the leaves. It is considerably simpler to prevent rust than to control an outbreak. Rust can be prevented to a large extent by watering from below, maintaining adequate air circulation, and doing a thorough autumn cleanup. To stop the rust from spreading further, any leaves that exhibit symptoms should be plucked from the plant and thrown away.

Overwintering: Hollyhocks can be cultivated as annuals in regions that experience harsh winters by sowing the seeds in pots and spending the winter indoors. When the weather starts to warm up, water them sparingly during the winter and gradually reintroduce them outside.

Prune them in the fall to a height of approximately 6 inches above the ground in other locations where they can be kept outdoors. Straw or mulch should be spread 4 to 6 inches thick over the plant's base and root zone. Remove in layers in the spring to allow the roots to progressively adapt. Remove all of the straw or mulch whenever new growth starts to appear. In case of a spring freeze, cover the plants again.