Dahlias are beloved for their vibrant colors, diverse shapes, and stunning beauty, making them a favorite among gardeners worldwide. Dahlias are flowering plants native to Central America, particularly Mexico. They belong to the Asteraceae family, which also includes sunflowers and daisies. Dahlias are known for their showy, colorful blooms, which come in a wide range of sizes, shapes, and colors. From small, pompon-like flowers to large, dinner-plate varieties, there is a dahlia for every garden.
There are thousands of dahlia cultivars, classified into various types based on their flower form and size. Some common types include:
Single-flowered dahlias: These have a single row of petals surrounding a central disc.
Anemone-flowered dahlias: These have a central disc surrounded by one or more rows of flat petals, giving them a daisy-like appearance.
Cactus dahlias: These have rolled or twisted petals that give them a spiky appearance.
Pompon dahlias: These have fully double, spherical blooms made up of tightly packed petals.
Dinner-plate dahlias: These have large, fully double blooms that can reach sizes of up to 12 inches in diameter.
Dahlias are typically grown from tubers formed in the prior growing season. When planting in the spring, ensure each tuber has at least one viable eye from which a sprout can emerge. Remember, the tubers themselves do not produce sprouts; they serve as food storage vessels to fuel the plant's early growth. Until the sprouts appear, the eyes may be challenging to see and easily damaged.
For garden planting, wait until the soil has warmed to 60°F. Dahlias won't grow in cold soil, and their foliage is sensitive to frost. In colder regions, start tubers indoors 4 to 6 weeks before the last frost date. Plant tubers in pots filled with moist growing mix, with the stem or sprouts facing up. Transplant outdoors after the risk of frost has passed.
Dahlias thrive in full sun and fertile, well-drained soil. Space border dahlia tubers 15” apart and standard types about 18” apart. Loosen the soil to a depth of 12”, add compost and fertilizer, then plant the tubers with the stem or sprouts upright, burying them 3-4” below the soil surface.
When dahlias reach about 12” tall with at least 4 pairs of leaves, pinch off the top of the main stem to stimulate lateral branching. This promotes stockier plants with more stems and flowers. While border dahlias may not need support, larger varieties may require staking or cages to protect stems and support flower heads.
Consistent watering and feeding are crucial for healthy dahlias. Drip irrigation directs moisture to the root zone while mulching reduces moisture loss. Apply a granular fertilizer at planting and liquid fertilizer monthly during the growing season to encourage abundant flowering.
Keep foliage dry to discourage disease, watering deeply once a week and allowing the top inch of soil to dry between watering. Clear foliage around the base of plants and remove spent flowers to promote good air circulation. Organic controls like Sluggo pellets can help manage pests like slugs and snails.
Dahlias are excellent cut flowers, and harvesting encourages more blooms. Share the beauty of your homegrown dahlias with friends, family, and coworkers by creating stunning bouquets.
Removing spent flowers keeps plants tidy, encourages new buds, and helps control pests and disease. Nip off flower heads or use scissors to cut back to a main stem to stimulate new growth and longer stems better for cutting.
