Whether their seeds are sown indoors or out, growing hollyhocks from seed is a rewarding experience. I like to say that hollyhocks are great for your gardening self-esteem because they grow from a tiny seed into a towering spire of colorful blooms with very little effort. A staple of every cottage garden, hollyhocks have so much to offer the landscape. In this article, I’ll share insight into how to grow hollyhocks from seed and how to ensure they return to your garden year after year.

Meet the hollyhock

Hollyhocks (Alcea rosea) are native to Asia and Europe, but they have called North America home for generations. Once known as “outhouse flowers”, tall, stately hollyhock blooms were used to block unsightly views of outdoor “facilities”. Nowadays, these pretty plants are grown in perennial gardens, along fences, next to buildings, and around mailboxes across the globe.

Most varieties of hollyhocks are biennials. This means that they produce only foliage in their first year. After overwintering, the plants then produce their colorful spires of blooms during their second year. When blooming is complete, the plants then set seed and die. Some varieties act more like short-lived perennials and can be coaxed into blooming their first year by sowing seeds indoors under grow lights to get a jump-start on the growing season. These varieties may even live for three or four years before succumbing after dropping their seeds.
Though their lives are short, hollyhocks are memorable and well worth growing. Bloom time is from June through August. Flowers occur in various shades of red, burgundy, pink, white, yellow, apricot, and fuchsia.

Where to grow hollyhocks

When growing hollyhocks from seed, it’s important to choose a planting site that meets all their needs. The plants prefer well-drained soil in a location that receives full sun to partial shade. I find the flower stalks stay more upright in locations that receive at least 8 hours of full sun each day. A yearly addition of compost to the areas where hollyhocks grow helps keep the plants well fed.

Because their flower stalks can become quite tall and somewhat top heavy, I love growing hollyhocks in front of a fence, trellis, or other structure. This makes staking the plants a breeze. Protect the plants from high winds by choosing a sheltered sight and providing support.

Hollyhocks are best grown in USDA hardiness zone 3-9, where first-year plants easily overwinter to produce their flowery stems the following season.

Another thing to consider when selecting the best site to grow hollyhocks is their tendency to drop a lot of seed. While this is mostly considered a good thing, self-sowing can also become problematic, so make sure you plant them in a place where this won’t matter. You can also cut off the spent flower stalks before they drop all of their seeds or be prepared to weed unwanted seedlings out each year. Do remember to always leave a few seeds drop so you’ll have at least a few plants returning to the garden next year.

When to plant hollyhock seeds

Hollyhock seeds should be planted in the late winter or early spring, depending on whether you plan to direct sow them outdoors or start them indoors under grow lights. Let’s discuss both methods.

Growing hollyhocks from seed indoors

The best time to sow hollyhock seeds indoors under grow lights is about 8 to 10 weeks before your average last spring frost. Here in Pennsylvania, I sow seeds indoors around early to mid-March. The plants will then be ready to be transplanted outdoors in mid-May, after the danger of frost has passed.

When growing hollyhocks from seed indoors, always use deep pots as the plants have long roots that do not like to be disturbed. Sow hollyhock seeds individually, with one seed per pot, and do not up-pot or otherwise disturb the plants until they are ready to be planted outdoors. Use a well-drained seed starting potting mix and run your grow lights for 12-16 hours per day.

You’ll start to see the seeds germinating in about 10-14 days, but they’ll need another 6 to 8 weeks of growth before they’re ready for the great outdoors.

Harden off the hollyhock seedlings by placing their pots outdoors in a shady spot for two weeks before they are ready to be transplanted outdoors. Gradually increase the amount of sunlight they are exposed to each day.

Growing hollyhocks from seed outdoors

For me, growing hollyhocks from seed outdoors is much easier and requires much less time and effort, so this is my preferred method. Thankfully, hollyhocks are always happy to oblige. Germination rates are always high if the seeds are not buried too deeply and they are “fresh”. The plants need little to no coddling—that’s one of the reasons so many people adore this plant.

Sow hollyhock seeds outdoors a week before your last spring frost. Plant them ¼ to ½ inch deep, making sure the planting site receives at least 8 hours of sunlight per day. Space the plants about a foot apart. Hollyhocks can form clumps that can grow quite wide, so give them plenty of room.

Growing hollyhocks from seed they sow themselves

Though they will often not bloom until the next spring, it’s fun to watch the foliage grow and develop through the first season. Once you have a colony of plants established, hollyhocks will self seed, ensuring they return to your garden every year. At the end of each flowering period, always let some seed drop (but not too much—consider yourself forewarned). You’ll have new plants popping up the following spring.
Seeds from short-lived perennial hollyhock varieties benefit from exposure to winter temperatures (called cold stratification) to break dormancy. They will have better germination rates if the dropped seeds are left outdoors all winter long. For biennial varieties, you can either let the seed naturally drop or collect the seeds and sow them indoors under grow lights the next spring.

I find it’s easiest to let the seeds drop and sow themselves, regardless of whether they come from biennial types of perennial types. This establishes a long-lived colony with some plants in bloom some years while other plants are only in their first-year without blooms.

Caring for hollyhock plants

Hollyhock plants need to be watered at the base of the plant until they are established. After that, they’re pretty self-sufficient.
Stake the tall stems using individual hardwood stakes or a trellis if necessary.

The plants require little in terms of fertilization. I add compost around the plants in early spring and that’s it.

The only other maintenance chore is to remove some of the seed pods at the end of the season if you don’t want a gazillion seedlings popping up the next year.

Hollyhock Pests

Hollyhocks do have a few potential problems to watch for.
Pests of hollyhocks include:

1. Slugs who love to much on the seedling leaves. They can be controlled with organic slug baits.
2. Japanese beetles who occasionally feast on the mature foliage and flowers in late summer. These pests are best removed by hand picking.
3. Spider mites who cause pale mottling on the tops of the leaves and a fine webbing beneath. Horticultural oils are an effective control.
4. Hollyhock sawflies (which look like little green caterpillars) who skeletonize the leaves in short order. They are found on the leaf undersides and can be quite tiny early in the season. Insecticidal soaps and Spinosad products manage hollyhock sawflies effectively, but I just get rid of them by pruning off the leaves that host them.

Hollyhock rust

The biggest issue with hollyhocks is hollyhock rust. This fungus causes small bumps and yellow spots on the tops of the leaves. When flipped over to view their undersides, the leaves are covered with rust to orange colored spots.

This pathogen spreads by spores. Though it often does not kill a plant, it sure makes it look scrappy. To prevent rust, space plants far apart to ensure good air circulation, water plants only at the base and keep the foliage dry. Remove all the frost-killed foliage and stems in the fall to prevent the rust spores from overwintering near the plants. Do not compost these materials. Fungicides based on sulfur and copper can be used as a preventative.

Happy, Healthy Hollyhocks

Despite the small handful of potential problems, hollyhocks are easy to grow and a welcome addition to gardens in a wide range of climates. As an extra bonus: they are also deer resistant. Pollinators such as bees, butterflies, and hummingbirds find the flowers irresistible (especially single-petaled varieties). Hollyhocks are also a host plant for the caterpillars of painted lady butterflies, making them as important as they are beautiful.

If you want to grow more flowers from seed, check out these articles:

• Growing marigolds from seed 
• Growing sweet alyssum from seed 
• Growing zinnias from seed 
• Growing nasturtiums from seed
• Growing pansies from seed