How to Grow Hollyhocks From Seed in 7 Simple Steps

Hollyhocks are an old-time biennial flower grown in gardens for centuries. They rise high above the garden with beautiful double or single-bloom flower stacks. Starting hollyhocks from seed is a common practice in the fall or spring, but they can also be purchased as bare-root plants or containers.

These flowers produce thousands of seeds and are easy to harvest. Once the flower is spent, cut or pinch it off the plant and remove the seeds from the head. Plant the seeds in a new location or share them with others who love the look of hollyhocks.

Traditional varieties are biennial; you will have to plant seeds 2 years in a row to get flowers every year. A few varieties will bloom and produce seeds in their first year. Let’s look at some simple steps to help you grow hollyhocks from seed, indoors and out.

Step One: Choosing Varieties

There are endless varieties of hollyhocks to choose from. These plants come in numerous sizes, from 3 feet tall to 8 feet tall. They can have single and double blooms that come in many colors. It can be overwhelming to choose from, but below are a few popular varieties to help in your search.

‘Nigra’

This dark single-bloom hollyhock is a true classic. It produces deep maroon, almost black large, single blooms. This variety has a mature height of 5 to 7 feet and attracts many pollinators. This variety will turn heads with its almost black blooms, a rarely seen bloom color.

‘Charters Double Yellow’

This beautiful golden-yellow double-bloom hollyhock has a mature height of 5 to 7 feet. Provide plenty of water and sunlight for the best performance. ‘Charters Double Yellow’ is a double-blooming variety. This will produce numerous ruffled petals all from one flower head.

‘Radiant Rose’

This is a delicate single-bloom variety that produces dazzling shades of pink. Blooming from mid-summer to late fall, the stalk of blooms grows from the bottom up. This variety is known for blooming in its first year when sown early in the spring. An excellent option for the impatient gardener like myself!

Step 2: Choosing Location

Deciding where to plant hollyhocks can be a struggle. Since they can get so tall, you must find a location where they won’t cover lower-growing plants. They are best grown at the back of flower beds, along buildings, fences, or walkways. The dwarf varieties can be grown in containers or low flowerbeds.

The species need plenty of sunlight. They can tolerate partial shade, but you should choose a location that receives 8 hours of sunlight per day for the best performance. This will encourage more blooms and taller stalks. They will continue to produce blooms and stalks in partial shade, but their production may be significantly less.

Step 3: Planting the Seeds

Hollyhock seeds can be planted outdoors in the fall or indoors in early spring. Depending on the season you choose to plant, more work will be involved in one over the other. Let’s take a look at planting seeds in autumn.

Fall Planting

If this is your first year planting hollyhock seeds, the easiest time to plant is in the fall. Planting in the fall will allow the seeds to lay dormant in the soil until conditions are ideal to germinate. Hollyhocks are very winter-hardy, and their seeds can withstand freezing soil conditions.

Once you have chosen your variety and location, work the soil so it’s loose and easy to create holes. Place the seeds into ¼-inch deep holes and cover them with soil. Seedlings should be about 2 feet apart. If you are worried about seeds dying over winter, you can plant closer and thin out once they have germinated.

These flowers need plenty of space to spread. Planting too close together can cause diseases like rust. Once conditions are ideal, your seedlings should sprout within 10 to 14 days. Planting in the fall is much simpler and less time-consuming than spring.

Spring Planting

If you plant in the spring, the seeds must be started in containers indoors. Consider starting indoors 6 to 9 weeks before the anticipated last frost of the season. Begin by gathering supplies. Below is a list of items to gather before planting indoors:

• 2 to 3-inch pots or celled planting trays
• Potting soil
• Seeds
• Light source (grow lights or south-facing sunny window access) 
• Water

Helpful Tip: Place your seeds in warm water to help soften the seed coat and encourage faster germination. This step isn’t necessary, but it speeds things up.

You don’t need a greenhouse to start your hollyhock seeds, but they do need access to adequate lighting. Fill your pots or cells with the potting soil and make a shallow hole, about ¼ of an inch deep. Place one seed per hole and cover it with soil. Water well and place in indirect sunlight.

Step 4: Successful Germination

Hollyhocks thrive in warm, moist conditions. Typically, it will take 10 to 14 days for your seedlings to germinate. There are some ways to promote germination.

Consider placing plastic wrap or clear plastic bags over pots or cells if planted indoors in spring. This will create a small greenhouse effect and keep temperatures and moisture high. This is a great option if you don’t have access to a greenhouse.

It may take longer for seeds to germinate if soils are too soggy or dry. Check your seedlings daily to ensure they are properly watered. Hollyhock seedlings prefer room temperatures around 65 to 75 F.

Step 5: Caring for Seedlings

Once hollyhock seedlings are 2 to 3 inches tall with a set of first true leaves, move them to a larger pot. A 3 to 4-inch pot should be enough room until you are ready to plant outdoors. The deeper the pot, the better. Hollyhock produces a large tap root that grows deep into the soil. Consider using pots 10 to 12 inches deep to allow for adequate growth. Be careful when removing to avoid breaking or damaging the seedling.

Upgrading your pots will require more space, be sure to find a location that will allow indirect sunlight to hit the pots. Direct sunlight can burn the seedlings and cause them to die. Intense sunlight will also dry your soil quicker. Monitor your seedlings to prevent the soil from drying out. Water frequently to promote proper growth.

Step 6: Hardening Off

Hardening off allows your seedlings to get acclimated to the outdoors. This can be beneficial in spring when the risk of frost is still present at night. In northern regions, frost can happen late in the spring. Your hollyhocks will love the bright sunlight but be protected from cold night temperatures.

To begin, place your plants outdoors 1 to 2 hours a day. Every few days, increase the time the seedlings are outdoors. This gradual increase will help the plants adjust to the temperatures and sunlight outside.

Bring your seedlings indoors every night to protect them from early spring chills. This process should only last a few weeks, and once the risk of frost in your region has passed, you’re ready to plant your seedlings outdoors.

Step 7: Planting Outdoors

It’s finally time to plant your seedlings outdoors. Begin by choosing a sunny, well-draining area to plant your hollyhock seedlings. Once you have identified a location, dig holes as deep as your pot height. This way, you can pull the hollyhock from the plant and place it directly into the hole.

Plant your hollyhocks about 2 feet apart. This will allow for spreading as the seeds drop each year. We don’t want to overcrowd the hollyhocks because this won’t allow proper airflow between each hollyhock. Lack of airflow can cause diseases like rust to grow and spread rapidly.

Cover with soil and water frequently for the next couple of days. We want to encourage root growth to establish a healthy plant.

Frequently Asked Questions