Planting flowers in August: guidance from a seasoned horticulturist
August: The Ideal Month for Garden Transplanting and Sowing
As summer reaches its peak, gardeners can make the most of the warm weather by sowing and transplanting a variety of flowers to ensure a vibrant display well into the autumn season. Here are some tips for successful gardening in August.
Fast-Growing Annuals for Late Summer and Fall
August is the perfect time to sow fast-maturing annuals that will bloom by September or October. Cosmos, with their vibrant pinks and other colours, are quick to mature (50-60 days) and thrive in well-drained soil and full sun. Zinnias, bright and cheerful, are another excellent choice, with many varieties maturing in 60-70 days, providing flowers through fall if planted in August.
Marigolds, Calendula, and Snapdragons are also ideal for August planting, offering late blooms and vibrant garden colour. The tall, bright-orange Mexican sunflower (Tithonia rotundifolia) and the vigorous, pale blue Morning Glory (Ipomoea ‘Caprice’) are also suitable for August planting, providing sustained colour into late summer.
Self-Seeding Annuals for Next Year's Blooms
For those who want blooms next year, self-seeding annuals like Love-in-a-Mist (Nigella damascena) can be planted in August. These easy-to-grow flowers make great cut flowers and, if they self-seed, can provide blooms for subsequent years.
Transplanting Perennials
August is also the optimal time for dividing and transplanting Astilbe, Delphinium, and Lilies. Delphinium seeds sown in August can achieve almost 100% germination in the spring, while Lilies should be transplanted in August once flowering has ended and bulbs have ripened. If lilies have long stems, they should be planted in pots or stored in the refrigerator until September.
For Ageratum, which can self-seed and blend well with bellflowers and petunias in warm winters, August is the best time for transplanting. However, if a variety of Bellflowers is still blooming in August, it's best to wait for the full end of flowering before dividing and transplanting. Bellflowers from the Carpathians can be sown directly in August, as they are undemanding and bloom for a long time.
Chinese Chrysanthemum and Daisies
For cold-hardy varieties, sowing Chinese chrysanthemums in August ensures stronger and more uniform germination. Daisies can also be divided and sown in August, but not all double varieties germinate well after winter sowing.
Violas
Violas can root, overwinter, and bloom in the spring when sown in August.
Regional Differences
These recommendations assume you have typical temperate climate conditions; the exact timing and success may vary by region and frost dates. Dahlias and other late-summer bloomers are also suitable for August planting in areas with warm weather.
In summary, August is ideal for sowing fast-growing annuals like cosmos, zinnias, and marigolds, as well as self-seeding flowers if you want blooms next year. Choose species suited to full sun with well-drained soil to optimize blooming before the first frost. Happy gardening!
Sources: - Gardening Know How - Gardens Illustrated - Homes & Gardens
August gardening offers an opportunity to sow fast-maturing annuals such as Cosmos, Zinnias, and Marigolds for a vibrant display by September or October.It's also the optimal time for transplanting perennials like Astilbe, Delphinium, and Lilies for a abundant bloom next spring.
