Dahlia ‘Sheer Heaven’ offers stunning, abundant blooms, adding beauty to any garden. This dahlia variety is a favorite for its prolific flowering and distinctive color palette, making it a highly sought-after plant. Cultivating Dahlia ‘Sheer Heaven’ provides a vibrant display from mid-summer until the first autumn frost.
Meet Dahlia ‘Sheer Heaven’
Dahlia ‘Sheer Heaven’ is recognized for its formal decorative bloom type, presenting lush, double flowers without a central disc. The petals unfurl in a captivating blend of soft peach, palest lemon yellow, and rosy blush pink hues. This color variation can shift slightly from flower to flower on the same plant or throughout the season, adding to its appeal.
Blooms typically measure 5 to 6 inches across. Dahlia ‘Sheer Heaven’ plants can reach a mature height of 4 to 5 feet, providing a substantial presence in the garden. These flowers are borne on long, strong stems, which are ideal for cutting and arranging.
Planting and Cultivation
Optimal planting for Dahlia ‘Sheer Heaven’ tubers occurs in spring, after the last frost and when soil temperature consistently reaches around 60°F. This period often falls between mid-April and mid-May. Gardeners in colder climates can start tubers indoors in containers approximately four to six weeks before the last expected frost to get a head start on the growing season.
Selecting the right site is important for healthy growth, with full sun exposure being ideal. Plants need six to eight hours of direct sunlight daily, particularly morning sun. The planting location should also offer some protection from strong winds, which can damage the tall plants. Dahlias thrive in rich, well-draining soil with a pH level ranging from 6.0 to 7.5.
Amend heavy clay soils with aged manure, compost, or peat moss to enhance drainage and aeration. Loosen the soil to a depth of at least 12 inches to allow the tubers ample space to expand. When planting, dig a hole approximately 4 to 8 inches deep, positioning the tuber on its side with the “eye” or growing point facing upwards. Cover the tuber with 2 to 3 inches of soil, gradually filling in the hole as the stem sprouts.
Space tubers about 12 to 18 inches apart for individual plants, or 3 feet apart if planting in rows. Avoid applying nitrogen-rich fertilizer directly at planting time, though incorporating some bone meal or compost into the planting hole can be beneficial. After planting, refrain from watering the tubers immediately unless the soil is exceptionally dry; wait until sprouts emerge or the first true leaves appear to prevent rot.
Ongoing Care and Maintenance
Once Dahlia ‘Sheer Heaven’ plants are established and about 24 inches tall, consistent deep watering is important, especially during dry periods. Aim for deep watering three to four times per week during summer, ensuring water penetrates at least 8 to 10 inches. This approach is more effective than shallow, daily watering. Container plants may require more frequent watering, sometimes daily, as their soil dries faster.
Dahlias benefit from regular fertilization to support their vigorous growth and prolific blooming. Once plants are around 24 inches tall, an early-season fertilizer, such as fish emulsion, can be applied monthly. As the season progresses, switch to a low-nitrogen fertilizer to encourage flower production rather than excessive leafy growth, applying it monthly or a foliar feed every two to three weeks.
Staking is often necessary for Dahlia ‘Sheer Heaven’ due to its potential height of 4 to 5 feet and the weight of its large blooms. Install stakes at planting time to avoid damaging the tubers later. As the plant grows, tie it to the stake every 12 to 18 inches to provide continuous support.
Regular deadheading promotes continuous flowering. Removing spent blooms redirects energy from seed production to new flowers. Snip faded flowers just above the nearest healthy set of leaves or buds. This also improves air circulation, deterring diseases.
Pest and disease prevention includes keeping the garden tidy to reduce habitats for pests like earwigs, and consistent watering to deter thrips. Avoiding overhead watering helps prevent fungal issues like powdery mildew. For aphids and spider mites, horticultural soaps are effective.
Overwintering Dahlia Tubers
In regions with cold winters, Dahlia ‘Sheer Heaven’ tubers must be dug up and stored. The optimal time is after the first hard frost kills the foliage, causing it to turn dark brown and mushy. Allowing tubers to remain in the ground for one to two weeks after this frost can toughen their skin for storage. However, if a severe freeze is imminent, it is important to dig them immediately, as frozen tubers will not survive.
Before digging, cut stalks to about 4 inches from the ground. Loosen the soil around the tuber clump with a pitchfork, starting away from the stem to avoid damaging tubers. Once lifted, gently brush off excess soil from the clumps. Label each tuber clump before cutting foliage for variety identification.
Some gardeners prefer not to wash the tubers, believing that leaving some dirt on them can aid in storage. After digging, allow the tubers to dry for a few days in a cool, dark, and frost-free location, though excessive drying should be avoided. Ideal storage conditions involve a temperature range of 38-50°F (4-10°C) and a relative humidity of 75-90%. Store tubers in paper bags, bulb crates, or boxes, ensuring good air circulation. Periodically check stored tubers for mold, rot, or shriveling, adjusting conditions as needed.
Common Challenges
Dahlia ‘Sheer Heaven’ can encounter several common challenges. Pests like aphids, spider mites, slugs, earwigs, and thrips are attracted to dahlia foliage and blooms, causing damage.
Fungal diseases like powdery mildew (white coating on leaves) and gray mold (dark, fuzzy growth on buds and flowers) can also affect plants. More serious issues include crown gall (swollen growths) or mosaic viruses (variegated or stunted leaves). Proper cultural practices, including good air circulation and appropriate watering, can help mitigate these issues.
If plants are not blooming, it could be due to overwatering early in the season or a fertilizer imbalance, particularly too much nitrogen.