What conditions do Hibiscus plants need to thrive?
There are various hibiscus types, but each has similar requirements. Hibiscus are typically easy to grow, but like most plants, they do have conditions that they prefer in order to really thrive and look their best. An excellent way to determine proper site conditions is by looking at the native habitat of Hibiscus.
Sunlight: Hardy Hibiscus is native to wet areas of the central and eastern U.S. You can find them growing in marshes, flood plains, and moist woodlands. These conditions tell us hibiscus thrives in areas with full sun but will tolerate light shade. It’s best to avoid heavier shade, as the plants will lack vigor and flower less.
Tropical Hibiscus is native to areas with warm year-round temperatures and full sun, making it critical to give them warm conditions. Doing so will promote healthy plants that produce an abundance of flowers.
Soil: A crucial part of growing hibiscus. These plants prefer soil that stays consistently moist, but they can tolerate drier conditions once established. Ideally, they should receive fertile soil rich in organic matter. Healthy soil will retain water and nutrients, allowing your hibiscus to thrive. Worried that your soil isn't up to snuff? Opt for a Rose of Sharon, which is more tolerant of poor soils.
Temperature: The requirements for temperature vary based on the type of hibiscus you're growing. As mentioned before, Hardy Hibiscus can be grown down to Zone 4 with protection. Some gardeners leave the old stems on the plant until spring, creating a layer of protection for the crown. Rose of Sharon is another hibiscus hardy to Zone 5. Just remember to give it time to leaf out, as it may be the last plant to break dormancy in your garden.
Tropical Hibiscus has very different requirements for temperature. Gardeners in tropical climates may never experience freezing temperatures. At the same time, gardeners living in the colder areas of Zone 9 will have freezing temperatures occasionally. Unlike many tropical plants, Hibiscus will survive a freeze down to the mid 20s for a brief period. Temperatures below 20°F will likely kill the plant. If you live in Zone 9, consider using an extra layer of protection when a freeze is in the forecast, like a thick layer of mulch around the base of the plant. Covering the Hibiscus with a sheet is also effective.
Space: Proper spacing is critical for growing any plant. Tropical hibiscus grows up to 5' tall and wide in the landscape, meaning you should space the plants about 5' apart when you plant them. Hardy hibiscus will reach 3-4' tall and wide, requiring you to space them 3-4' when planting them.
Rose of Sharon can get much larger than Tropical and Hardy Hibiscus, sometimes growing up to 8 ft wide, depending on the variety. Therefore, you should space them further apart compared to other hibiscus. However, some varieties of Rose of Sharon are shorter and compact. Always check the plant tag before planting.
Water: Hibiscus grows in wet habitats, making them valuable plants for landscapes with moist soil. They can thrive in drier soils, too (Rose of Sharon is especially tolerant of drier soils); just be sure to keep them well-watered until they become established. Consider planting in late spring or early summer to establish your plants before winter. Installing plants earlier in the growing season will strengthen the plants and prevent them from drying out in winter.
Pests: Hibiscus are not especially prone to pests, but you may encounter them occasionally. A few common insect pests are aphids, mealybugs, caterpillars, and Japanese beetles. Only use insecticides as a last resort, when you know what type of pest you're dealing with, and follow directions on the label.
Japanese beetles have become a widespread problem in parts of the country. One method of dealing with this pest is handpicking the beetles off the plant and putting them in a bucket of soapy water. Early morning is ideal for removing the beetles, as they are sluggish. You can also use a targeted insecticide if handpicking is not working.
Prevention is critical for pest control, and the best way to prevent pests is to give your hibiscus proper care.