Hollyhocks grow in USDA zones 3 to 8 as biennials, i.e., they can grow for approximately two years. However, with proper care, these plants can have an increased lifespan to become short-term perennials. Regular removal of dead flowers ensures that the plant gets new blooms.
Hollyhocks, or alcea, are very popular flower garden plants. There are around 50 species which flower in many different colors, like, purple, pink, yellow, white, etc. These plants can be identified by their erect unbranched structure, and big leaves that are either lobed or toothed in shape. The flowers may grow solitary or in groups, all along the stem.
These plants can grow up to a height of 10 feet in the right conditions, which suits gardens that have a tall wall or fence in the background. Hollyhocks are easy to grow from seeds, and they are a good choice to attract pollinating insects and hummingbirds. Some species are used in alternative medicine, and the branches of fully-grown plants are used as firewood in some places of Asia and Europe. With all these positives, you will definitely want to include the hollyhock in your garden.
How to Sow Hollyhock Seeds
Hollyhocks need soil which is rich in nutrients, has a good moisture content, but drains easily. Soil which is too dry will stunt the growth of this plant. Sow the seeds at least two feet apart, and no more than half inch deep. Make sure that you plant the seeds in a place which receives a good amount of sunlight. Water the soil so that it never completely dries out. The timing of planting the seeds is also important. Plan the planting to around two weeks after the last frost. Usually, hollyhocks grow flowers only during the second year. However, to increase the chances of flowering in the first year itself, plant the seed indoors, in trays of sandy soil during the fall season. Saplings will usually germinate in 1 or 2 weeks. Then, these plants have a good chance of flowering in the coming spring.
How to Grow Hollyhock Plants from Seeds
Once the seeds are planted, you can leave them to grow without much interference. There are only a few things you need to look out for:
- Water the plants well twice or thrice a week.
- If you are growing the seeds indoors, transfer the seedlings from the tray to individual pots after germination, and let them grow there till spring. The pots should be kept in a place where they get enough sunlight. The plants should be replanted outdoors in spring.
- To take special care of the hollyhock after blooming, regularly pick off and discard any dying flowers that you see, and do some light pruning. This will increase the lifespan and flowering capacity of the plant.
- If you live in a place that doesn't have a tropical climate, cut the plants down to a height of 5 or 6 inches, and mulch them once they finish flowering and stop producing seeds. Use charcoal ash for this purpose, if available. This protects the plants till the next flowering season from harsh climate and some pests. Ideally, you should remove the mulch after the frost has completely gone.
- Hollyhocks produce seeds very vigorously. Collect these seeds and store them, so you are ready to plant new seedlings when the present plant eventually dies.
- Applying a compost or fertilizer during spring and summer at the base of the plant will help it grow even better.
Common Hollyhock Diseases and Pests
The hollyhock is a very robust plant, and is resistant to most diseases and pests. However, if you notice any of the following diseases or bugs on the plant, you will need to take appropriate action.
This is an infection caused by a fungus called Puccinia malvacearum. The fungus causes the plant growth to stunt, and destroys the chlorophyll in the leaves, causing them to fall. This disease can be identified by small yellow or brown spots on the bottom of the leaves, and large spots on the top. Since the infection spreads from the base of the plant to the top, keep a regular lookout at the base to start an early cure.
To prevent rust from forming on the plants, sow the seeds away from each other, to allow for good ventilation between the hollyhocks. Make sure to water the base, rather than all over the plant. Less or excess watering can make it easy for the fungus to afflict this plant.
If rust has already affected your hollyhock, first remove and destroy all infected leaves on the plant. If an entire plant has been affected, uproot and discard the plant, so that the rust does not spread to other hollyhocks. Do not leave any dead leaves, flowers, or cuttings on the ground, as dying matter attracts fungus. Also, do not use any diseased plant parts in your compost. Use fungicides that are formulated specifically for getting rid of rust.
Weevils are small gray insects with red legs. These insects reproduce very fast, and can cause major damage by burrowing into the stems, flowers, and seeds to get food. For light infestation, put some cloth under the plants, and shake the weevils off the plant onto the cloth. Drown the insects in a bucket of soap water. For a large infestation, using a good pesticide made specifically for weevils is the only solution.
Caterpillars and Slugs
These pests usually do not cause a lot of damage to the plants. However, if you do need to get rid of them, slugs can easily be killed with common salt, while caterpillars can just be thrown away from your garden.
These insects are usually a threat to young plants, by eating through the stems and leaves. The larva, usually around two inches long, and are either pink, gray, black, or green in color. They are active during the night, and one can find them curled up near or on the plant during the day. Carefully applying BT bacteria or eggshells around the base of the plant will effectively stop this pest. There are certain insects which prey on these larvae. They can be bought at a garden center, and released near your hollyhocks.
Caring for hollyhocks is easy and does not take a lot of time. So, following these simple hollyhock plant care steps will allow you to enjoy the company of these plants in all their splendor every year.