Download Hibiscus Provides a Touch of Tropics

Hibiscus Provides a Touch of Tropics
By Diane Betts, Colorado Master Gardener
What is it: Hardy Hibiscus (Hibiscus moscheutos)
Rose Mallow or Swamp Mallow
Appearance: Your first thoughts about Hibiscus may
recall the tropical species that do so well in Miami and
Hawaii. Forget that and think HARDY hibiscus hybrids.
These incredible hybrids can add a touch of the tropics
to your Colorado yard well into late summer when
everything else is fading fast.
Hybridized by a family of three brothers in the 1950's,
hardy hibiscus shrubs combine the hardy nature of
their wild ancestors with brilliant tropical blooms. In
addition, their upright, mounding branches and dark
green foliage offer a compact growth habit better suited
for containers, borders and our backyard gardens
versus the rainforest.
Once established, the shrub produces several stems
from the ground that can reach 4 to 5 feet high. Delicate, ruffled, crepe-paper like 5-petal blooms are
7-inches across with prominent veins radiating out from the center and enlarged stamens and pistils.
Each stem can produce single or multiple flowers. The dramatic blossoms on this “Robert Fleming”
variety will last only one day but mature plants with plenty of moisture produce enough flowers to
make for a long show, blooming from August until the first frost. The flowers are great for attacking
bees, butterflies and hummingbirds. More than likely, the plant will need staking and protection
against high winds. Perennial hibiscus plants have no severe pest of disease problems.
Landscape Use: Keep the size of the mature hardy hibiscus in mind before planting. Select a site
that will be able to handle a 4-ft. tall and 3-ft. wide shrub. Hardy hibiscus loves the heat of the
summer and can handle full sun to part shade. Widely adaptable, the plant can handle a range of soil
but they do best in moist, organically-rich soils. So before planting add some peat moss especially if
your soil is predominately clay. Because it is a perennial, the plants need feeding in the spring. As
the shoots arise, apply a time-released organic fertilizer with plenty of phosphorus to encourage
blooms.
Stop feeding after June to ensure that flower production is not impeded by the excess nitrogen.
Hardy hibiscus need very little care over the winter. Just cut the plant back to about a foot from the
ground after the first frost. Add a layer of mulch and remember to shovel snow on top of the mulch
because it is better to keep this plant cold, not warm. Remember where you plant these
beauties…the plant is slow to appear in the spring, and you will not see them re-sprout until their soil
is at east 70 degrees.
Cultivation: It's best to plant hardy hibiscus before the heat of summer – give them a couple of
months to become established. Hibiscus blooms form on new wood so annual pruning is essential to
maintain a well-shaped bush. In spring after the damage of first frost passes, prune the remaining
dead growth back to the crown of the plant. As the plant grows, you may need to prune it before it
reaches its optimal height. This will help the plant remain full and bushy and prevent the bottom from
getting that ‘leggy’ look.
Hibiscus moscheutos cultivars were named by the Fleming brothers and are usually referred to as
'Fleming hybrid hibiscus.' They range in color from mild to wild and have names to match: “Torch,
Royal Gem”, “Fireball”, and “Fantasia”. “Plum Crazy” has 10-inch lavender-plum/pink blooms with dark
eyes and purple veining. The maple-shaped leaves are also plum-colored. This is a compact 4-foot
high shrub.
“Peppermint Schnapps” is exactly what you would expect. Drink it in! Bubblegum pink flowers are
striped with streaks of deep reddish pink throughout the petal. They match the bright red eye in the
center of each flower. This particular cultivar has a sturdy, upright habit with good branches.
Peppermint Schnapps is easy to grow and very adaptable and is a perfect size for large containers or
a sunny border.
“‘Cranberry Crush” has 7-inch deep scarlet red flowers with heavily overlapping petals. Mature size is
3 - 4 feet wide and 4 feet high. Blossoms will cover the full, compact plant from midsummer to early
fall and better yet, its flowers are produced at the nodes up and down the stems and not just at the top
like most other cultivars. They are set against a perfect backdrop of glossy deep green, leathery,
maple-like leaves with slight purple overtones.
For Do-It-Yourselfers, you can propagate hardy hibiscus with cuttings in early spring. Start by taking a
4 to 6-inch long cut from new growth or soft wood. Remove everything but the leaves and dip the
bottom into a rooting hormone. Using a pencil, make a hole in a rich, well-draining potting mix and
insert the cutting. Push the soil up and around the cutting to stabilize your new plant. Cover with
plastic and keep soil moist. (Do not let the plastic touch the leaves.) Once roots appear (in about 8
weeks) you can transplant to a larger pot.
When you have questions, your Colorado State University Extension office has research-based
answers. For answers to your horticultural questions, contact the Colorado Master Gardener Help
Desk at 520-7684 or email [email protected].
Extension Programs are available to all without discrimination.