Tips On Growing Helianthus (Sunflower)
Helianthus (Sunflower) are showy late summer/early fall blooming native wildflowers that are deer and rabbit resistant. There are both annual and perennials sunflower varieties.
Preferred growing conditions:
- Both annual and perennial Sunflower varieties grow easily in all types of soil including clay.
- Plant in full, hot sun.
- Sunflowers do not need to be mulched, but when planted in a garden with other plants that are mulched, they amenable to most common types of mulch including crushed gravel in xeriscapes.
- Perennials like Helianthus maximiliana and its hybrids are xeric (waterwise). After becoming well established by their second growing season they do best with deep but infrequent watering. Too much water makes them tall and floppy; it’s best to grow them on the dry side.
- Annual types need regular irrigation when there has been no rain.
- Perennial types just need a few handfuls of compost and Yum Yum Mix in the planting hole to get them off to a good start.
- Annual types benefit from more extensive soil preparation and will grow more vigorously when the soil has rototilled or dug to a depth of 8 to 12 inches and enriched with ample compost and Yum Yum Mix.
- Undaunted® Lemon Max hybrid perennial sunflower sets a lot of seed. If re-seeding is not desirable, it should be deadheaded shortly after blooming has finished to reduce the number of volunteer seedlings.
- Maximilian sunflower varieties are very vigorous growers that spread via underground roots. They should not be planted in flower beds with good soil as they will crowd out their neighbors; they are best planted in poor soil sites along fences, empty walls and other peripheral areas where their large size is an advantage.
- Sunflower seeds are a favorite food of many songbirds, so don't deadhead the plants after blooming.
- Leave perennial plants standing over the winter and cut them back hard to a height of 1-2" in early to mid-spring.
- Perennial varieties are easily divided in the spring to propagate additional plants or keep them in bounds if they grow too wide.
- The seed of annual varieties should be planted when the soil begins to warm up in late spring. Sow seeds at the same time when planting corn in your area.
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