To achieve the enchanting appeal of an English cottage garden, understanding the appropriate timing for planting hollyhock seeds is essential.
These stunning funnel-shaped blooms—available in shades of pink, red, purple, yellow, or white—grow on tall stems that can reach 6ft (1.8m) or more during summer. Hollyhocks (Alcea rosea) create a magnificent visual impact. Additionally, single-flowered versions attract pollinators like bees and complement plants such as foxgloves, bellflowers, and lupins.
Our guide provides all the insights needed for planting these lovely additions to your garden, allowing you to realize your flower bed ideas and enjoy their vibrant colors and height throughout summer and early fall.
When to Sow Hollyhock Seeds
For optimal growth and to minimize the risk of rust, a common fungal disease, it's best to cultivate hollyhocks as biennials.
According to a hollyhock specialist, 'Hollyhocks are generally viewed as short-lived perennials, commonly grown as biennials, meaning they flower in their second year.'
Consider trying Alcalthaea, closely related to hollyhocks, which are also fantastic short-lived perennials.
This guide offers timely information on sowing hollyhock seeds and their relatives.
Sow Hollyhock Seeds in Spring
Growing hollyhocks from seed is straightforward. For spring planting, seeds can be started indoors in March, April, or May, or directly sown outdoors in May, June, or July. Remember, as biennials, they won't bloom until the following year.
'When starting seeds indoors, lightly cover them with soil,' advises a gardening expert, 'and keep the temperature around 70°F (21°C). Germination usually takes 10 to 14 days. If your greenhouse is cooler, around 60°F (15°C) will work too, especially with a propagator.'
'I typically sow hollyhocks in April,' the expert continues, 'so they can establish before being transplanted, but they won't flower until the next year.'
Since the seeds are relatively large, sowing them in module trays, with one seed per module, is recommended.
Plant Hollyhock Seeds in Fall
Hollyhock seeds can also be sown in late summer or fall. 'I often plant under cover around September,' the expert shares. 'This strategy aims to encourage flowering within a year. I use 3in (7cm) pots, giving the plants a better chance to bloom in their first summer after transplanting the next year.'
New seedlings can be overwintered in a cold greenhouse, cold frame, or on a chilly windowsill.
Plant Hollyhock Seeds for Two Consecutive Years
Hollyhocks can self-sow, providing free plants if you skip deadheading. However, since they are biennial, a second sowing is necessary to guarantee annual blooms. This same principle applies if you grow foxgloves.
In spring or fall, you can relocate self-sown seedlings to your desired spots in the garden.
There's a wide variety of hollyhocks available for planting. Some favorites include 'Mars Magic' (a striking red), 'Halo Lavender' (a rich purple with a light center), and 'Peaches 'n' Dreams' (a double variety that rivals the beauty of peonies).
When to Plant Alcalthaea
Alcalthaea, a delightful cross of hollyhock and marshmallow, are bred for their stunning blooms and reduced risk of rust. These healthier perennials thrive longer than typical hollyhocks, growing wider, branching plants that form a goblet shape. They can reach 8ft (2.4m) tall and bloom from July to October, enhancing your garden borders.
Purchase alcalthaeas like the stunning 'Parkallee' as ready-grown pot plants, and plant them in well-drained areas with sunlight in spring or early summer or during fall.
How Long for Hollyhock Seeds to Germinate?
Hollyhocks take about 10 to 14 days to sprout, followed by an additional three to four weeks before they're ready for pricking out. When sowing indoors, ensure seeds aren't buried too deeply; a light soil covering suffices.
Do Hollyhocks Bloom in Their First Year?
Being biennials, hollyhocks do not flower in their first year as they focus on establishing roots and foliage. To achieve blooms every year, sow hollyhock seeds for two consecutive years. Once flowering concludes, you can either deadhead or allow them to go to seed for returning blooms.
