Giant perennial hibiscuses are one of the most popular of all perennials. They're excellent as a background for shorter perennials or planted individually throughout the yard. Their dramatic color and tropical flair will add charm wherever you plant them.
Quick Reference Planting Guide
- Location: Full sun.
- Hardiness: Zones 3–9 to -30°F.
- Planting Distance: 3'–4' apart
- Mature Height: 3'–6' or taller with a 3'–4' spread within two years. Some select varieties can grow 6'–8' tall with a 4' spread.
- Bloom Time: Mid-summer through fall frosts.
- To Plant: Dig a hole twice the size of your hibiscus' pot. Carefully remove the plant from the pot. Hold the root ball in the hole with the top level with soil surface, and carefully fill in around the root ball. Firm soil around the plant with fingers. Water thoroughly after planting.
Giant hibiscuses do well in most gardens, but for optimum results, improve soil quality as follows:
- Spade or rototill the soil to a depth of 12"–15".
- Thoroughly mix in a generous 2"–4" layer of dehydrated manure, garden compost, shredded leaves, or peat moss. Whether you have poor or rich soil, regular feeding with a flower booster will provide the ideal conditions for superior growth and blooming.
- Watering: Although the hibiscus is tolerant of heat and dry conditions, be sure to water weekly, especially when rainfall is less than 1" a week. A 2"–4" layer of mulch will help retain moisture and keep weeding to a minimum.
- Weeding: While mulch will help keep weeds down, be sure to keep the area free of weeds and debris. Walk around your plants on a weekly basis and pull weeds by the roots as soon as you see them.
- Winterizing: After frost causes the foliage to wither and die, cut back the stalks to ground level. Your giant hibiscus is perennial and will send up new stalks late the following spring/early summer. After you cut back to the ground in the fall, you can still mulch if necessary. However, remove the mulch in the spring as soon as temperatures start to rise.