Hollyhock Seeds: How and When to Collect and Plant Them

To achieve the traditional look of an English cottage garden, it is essential to know the right time for planting hollyhock seeds. Moreover, hollyhocks (Alcea rosea) are truly impressive, boasting charming funnel-shaped flowers in pink, red, purple, yellow, or white hues. These flowers bloom on tall stems that can reach heights of 6ft (1.8m) or even more during the summer season. Additionally, the single-flowered varieties of hollyhocks serve as a vital food source for pollinators like bees. They also complement other flowers such as foxgloves, bellflowers, and lupins.

Our comprehensive guide provides all the necessary information on when to plant these stunning backyard beauties. By following this guide, you can bring your flower bed ideas to life and relish the splendid height and colorful display of hollyhocks in both summer and early fall.

When And How To Harvest Hollyhock Seeds

How to Save the Seeds

Understanding the growth cycle of hollyhock plants is immensely helpful for those interested in harvesting hollyhock seeds. As biennials, hollyhock plants undergo germination, growth, and blooming within a span of two growing seasons. One of the characteristics of the first season is the development of abundant foliage, forming large mounds of leaves. After overwintering, new growth emerges in the spring. During the second summer, the plants elongate, and flowers bloom along the entire length of the stalk. Bees frequently visit hollyhock blooms, facilitating easy pollination. Gardeners should wait a few weeks after the flowers fade before attempting to harvest the seeds.

Hollyhock Seeds

Seed pods start to form at the base of each spent flower, and as they progress, the faded petals drop from the plant. Typically, these hollyhock pods display a light green color and a somewhat flat appearance. Over time, the pods transition from green to shades of tan or brown, and when they become dry or papery, they are ready for harvesting. The mature seeds within the pods are dark brown and often arranged tightly in a coin-like pattern around the center.

To collect the seeds, it is essential to remove the dry seed pods from the plant, while wearing gloves to protect sensitive skin from hollyhock irritation. Harvesting the seeds at their peak maturity is crucial, as seeds harvested too soon may rot or fail to germinate. Although leaving the seeds on the plant for an extended period may be tempting, it could lead to the mature pods cracking open and releasing the seeds into the garden. Consequently, experienced gardeners have found hollyhock plants to be vigorous self-seeders.

Storing the Seeds

Once harvested, it’s important to let mature hollyhock seeds dry for an additional one to two days. Afterward, you can store them in a cool and dark location until the planting season arrives. While growing hollyhock plants demands considerable patience in the initial seasons after planting, the subsequent successions of these flowers are guaranteed to bring a timeless charm year after year.

When to Plant Hollyhock Seeds

To decrease their vulnerability to a fungal disease called rust, it is recommended to cultivate hollyhocks as biennials. According to Jonathan Sheppard, the holder of the UK national collection of hollyhocks, these flowers are now considered short-lived perennials, often grown as biennials, resulting in flower production during their second year.

Moreover, closely related to hollyhocks, Alcalthaea are fantastic short-lived perennials that offer great value when introduced to the garden.

For those seeking the optimal timing to plant hollyhock seeds and alcalthaea, this provides the inside track.

Hollyhock Seeds

Plant Hollyhock Seeds in Spring

When it comes to hollyhocks, growing them from seed is a breeze. Regarding the ideal timing for planting hollyhock seeds, you have the option to sow them under cover in March, April, or May. Alternatively, you can sow them directly into the soil outside during May, June, or July. However, since they are biennial, it’s essential to bear in mind that they won’t bloom until the following year.

For indoor sowing in spring, Kelly Funk, President of Park Seed, advises barely covering the seeds with soil while maintaining a temperature of 70°F (21°C). Germination usually occurs within 10 to 14 days. In case your greenhouse doesn’t reach that temperature, 60°F (15°C) will suffice, and you can achieve this by using a propagator.

Jonathan Sheppard follows a similar approach and typically does a hollyhock sowing around April. This allows the plants to establish themselves and get planted out, but flowering won’t occur until the subsequent year. Given that hollyhock seeds are fairly large, it’s best to sow them individually into module trays, with one seed per module.

Plant Hollyhock Seeds in Fall

Furthermore, an alternative option for planting hollyhock seeds is during late summer or fall. According to Jonathan Sheppard, he frequently conducts a sowing under cover around September. The primary goal here is to attempt to outsmart the biennial nature of hollyhocks and achieve flowering within 12 months. To enhance the chances of early flowering, Jonathan uses 3in (7cm) pots for sowing. This way, the hollyhocks have a much better opportunity to bloom in their first summer after their transplantation the following year.

Once the young seedlings are in pots, you can overwinter them in a cold greenhouse, cold frame, or even on a cold windowsill.

Alcea Rosea

Plant Hollyhock Seeds Two Years Running

In addition to the ease with which hollyhocks self-sow, resulting in complimentary plants (unless deadheaded), it’s crucial to remember their biennial nature. To ensure yearly blooms rather than every other year, a second sowing must take place the following year—a principle similar to that of growing foxgloves.

When spring or fall arrives, you can relocate the seedlings that have scattered themselves throughout your backyard to the desired growing positions.

The variety of hollyhocks available for sowing is extensive. Some of Jonathan Sheppard’s top picks include ‘Mars Magic,’ which is a vibrant red variety that truly stands out in the garden. There’s also ‘Halo Lavender,’ an exquisite hollyhock with a rich purple hue and a light center. Lastly, ‘Peaches ‘n’ Dreams’ is a double variety whose blooms rival those of growing peonies.

When to Plant Alcalthaea

Moreover, Alcalthaea, the stunning offspring of hollyhock (Alcea) and marshmallow (Althaea), have been selectively bred for their remarkable flower power and increased resistance to rust, a fungal disease that often affects hollyhocks. This triumph of breeding results in healthier perennials with significantly longer lifespans compared to common hollyhocks. These perennials develop wider, branching plants that take on a beautiful goblet shape. Reaching heights of up to 8ft (2.4m), they exhibit a prolonged blooming period, sometimes from July all the way into October, making them a fantastic addition to any border.

For those interested in acquiring alcalthaeas, such as the beautiful ‘Parkallee’, it is advisable to purchase them as ready-grown pot plants. Plant these specimens in well-drained borders that receive ample sunlight during either spring or early summer, or alternatively, consider planting them in the fall.

Alcea Rosea

FAQs About Hollyhock Seeds

How Long Does It Take for Hollyhock Seeds to Sprout?

When sowing hollyhocks indoors during spring, it is crucial to avoid planting the seeds too deeply. The barest covering of soil is all that is necessary for successful germination, which typically takes around 10 to 14 days. After germination, you’ll need to wait an additional three to four weeks before the seedlings are ready for pricking out.

Do Hollyhocks Flower in The First Year?

Due to their biennial nature, hollyhocks do not bloom in their first year. In the initial year, their focus is on establishing strong roots and healthy foliage. The real floral display occurs in the second year when they finally produce flowers. To enjoy hollyhock blooms every year, it’s essential to plant hollyhock seeds consecutively for two years.

Before you go, you really need to learn more about the health benefits of Crocus Sativus (Saffron).

Other Flowers and Plants


Leave a Reply

Your email address will not be published. Required fields are marked *