Planting Instructions for Hibiscus (rose mallow, perennial hibiscus):
|Bloom Time: Summer and Fall
||Light: Full sun to part sun
|Soil: Humus-rich, moist but well-drained
||Moisture: Dry when dormant, regular watering when growing
|Planting Depth: 2 to 4" deep, top with 1 to 2" of mulch
||Spacing: 36" or more
Upon arrival: Unpack box and check that you have everything on your packing list. Bare root Hibiscus can be dry while dormant but should be planted within a day or two.
Soil/Location: Plant your Hibiscus in full sun to part sun in humus-rich, moist but well-drained soil. Avoid too much shade as this can cause some varieties to get too leggy plus plants will be much more prone to damage from the Hibiscus sawfly. They also prefer a garden that gets regular water in the summer but stays somewhat dry in the winter. Add compost or peat humus to enrich and loosen the soil and remember to keep the soil light and airy for perennials, so cover them with loose soil and don't pack the ground after planting.
Moisture: Hibiscus enjoy consistent moisture while actively growing in the summer however they should never be given supplemental water while dormant or they could fail to sprout and may eventually rot. Once established the deep tap roots help them to be fairly drought tolerant but regular water will help them bloom from summer until frost.
Spacing: Give each plant 36" or more of space, although they can be underplanted with spring flowering bulbs or groundcovers.
Depth: Plant with the top of the crown about 2 to 4" below the soil so that a good portion of the old stems are buried. New sprouts will only emerge from below the soil and any new buds (bumps at the top of the crown/base of the stems) must be covered. Top with 1 to 2" of mulch after planting.
General Instructions: Amend your garden with compost or peat humus to enrich and loosen the soil. Dig a large enough hole so that the roots are not broken or coiled too much then mix a couple tablespoons of garden food or bone meal into the bottom of the planting hole. Plant the roots at the depth listed above, backfill and then water in once. They prefer a dry start when they are dormant in spring and have no foliage so you should not water them again until they are up and growing and have formed their first set of full leaves. They also should never be given any liquid fertilizer when dormant but don't mind a light foliar feeding later in the summer. Once they are actively growing they enjoy deep watering 2 to 3 times a week or as needed if the soil becomes dry and they wilt.
Landscape Uses: Perennial Hibiscus grow to be large plants with shrublike proportions and work as foundation, anchor, or accent plants in the perennial garden. Because they die back in the winter and come up somewhat late in the spring you can underplant them with spring bulbs or short groundcovers like Ajuga or creeping Sedum to avoid having a bare spot in the garden. Then combine them with other summer blooming plants like daylilies, lilies, clumping Sedum, Echinacea, and hardy Geranium or if you really have a lot of room combine them with Helianthus and large ornamental grasses for a terrific late summer show.
Japanese beetles and the hibiscus sawfly are pests that can attack the flowers and foliage, respectively. Dusting with Sevin and/or spraying with Orthene or another systemic insecticide two to three times per year will help prevent damage.