Sea Hibiscus Is Not Just For The Beach

Sea Grass
Sea Grass
Sea Grass
Sea Grass
Sea Grass
Sea Grass

By Anita Westervelt, Cameron County Master Gardener, Rio Grande Valley Chapter, Texas Master Naturalist

A variegated leaf is a thing of beauty! The leaves of tri-color sea hibiscus especially so, with their velvety, creamy whites and contrasting variations of green. Add flashes of crimson and burgundy on new leaf growth, and you’ve got an ever-changing gallery of fine art in your garden.

Tri-color sea hibiscus, Hibiscus tiliaceus, is in the Malvaceae, (mallow) family, as are cotton and okra. Sea hibiscus is native to the Pacific Basin. It is an introduced species to Hawaii and the lower 48 states, especially popular in South Florida. It loves the humidity of Deep South Texas, and though not native to the Valley, it’s worth considering if you have a spot for it.

Give this tropical tree a lot of space. It can reach heights more than 20 feet and sprawl nearly as wide. It’s best planted at least 15 feet from a house, walkways and drives. After a tropical storm, or healthy rain, sea hibiscus can take off in all directions, its big, heart-shaped, marbleized leaves providing interest year after year.

Sea hibiscus grows extremely fast, especially with regular watering. This is a plant that can reflect a personal art form with pruning or be left to present a grand backdrop; used as a barrier hedge or strategically placed, it can camouflage an annoying view.

Left to its own devices, sea hibiscus branches artfully design their own shape, much like those of mesquite, but sturdy enough to not self-prune as often. Lower branches can be left to flow to the ground or travel along it for a full, massive bush.

Alternately, the low-growing branches can be pruned and the tree encouraged into a more traditional shade tree shape. The wood is soft, allowing easy pruning if it gets too unruly. Some note that it can be kept to a small size with an annual hard prune in late March or April.

Water it in well if planting during the summer, and then every day for a few weeks while it is getting established. To help promote leaf growth, commercially-purchased composted cow manure and top soil can be added to the hole when planting. Fertilizing shouldn’t be needed but for those who do like to give added nutrients, a good quality, granular fertilizer can be scattered under the understory three times a year during spring, summer and fall.

During hot summer months, traditional hibiscus shaped flowers, lasting only a day, open yellow in the morning and turn a burgundy red by day’s end.

Sea hibiscus prefers full to partial sun, and most any soil type. They do best in the warmth of Zone 10a. Being salt-tolerant, this tree is a great choice for beach properties; trees will be larger further inland in well-drained soil.

A small draw-back to these spectacular tropical glories, is that a cold spell will cause the leaves to shed. If that happens, mulch the dropped leaves with a mower and allow them to be left under the tree and out to the drip line. New leaves will push out on the branches again come spring, and within weeks the tree will be full again.