Tropical or Chinese hibiscus (Hibiscus rosa-sinensis) is not winter hardy in our climate and must be
brought indoors for the winter. It is difficult to say what kind
of hibiscus you have from your description, although its
performance indoors leads me to believe that yours is a tropical
Hibiscus syriacus 'Diana'
1991 Gold Medal plant award
'Diana' is winter hardy
Zones 5 - 8
(Click to enlarge)
hibiscus is an attractive houseplant if you can give it the very
bright light it requires to grow and bloom well indoors. A west
or south-facing window that gets five or six hours of direct sun
daily is best. It sounds as though yours is getting adequate
sun since it is still blooming.
Use an Unheated
Even without ideal conditions, you can keep a Chinese hibiscus
alive through the winter. A cool (50 - 60°F) place such as an
unheated, attached garage where it can get some light works
well. It will lose most of its leaves and all of its flower buds
when you move it into such a situation. However, the plant
should survive the winter and leaf out in spring when
temperatures warm and you can place it outdoors again. Be sure
the overwintering location you choose will not fall below 50
degrees. Temperatures lower than that can severely damage
Adequate, but not excessive watering is important for winter
survival. Chinese hibiscus prefers evenly moist soil, but it
should drain well to avoid a perpetually waterlogged condition.
Conversely, you do not want the soil to dry out to the point
where your hibiscus wilts. The pot it is growing in must
have drainage holes. How often you water depends on a number of
amount of sun the plant receives indoors. Plants that receive
enough sun to continue to grow and bloom indoors use more
moisture than those overwintered in darker locations where they
• The size
of the container it is planted in. Larger pots hold more
moisture than small pots.
potting mix. Very light, soilless mixes dry faster than those
that contain soil.
the container is plastic or clay. Plastic pots tend to hold
moisture longer, while porous clay
pots lose moisture from the sides as well as the soil surface.
Plastic pots are fine as long as you do not overwater.
temperature. Plants grown in warmer (65 – 75 degrees) locations
use more water than those grown in cool locations.
relative humidity in your home.
will not have to water as often as you did when it was actively
growing and blooming outdoors. Feel the soil two or three inches
deep, and water when it feels dry. Carry it to a sink or
bathtub and water until water runs from the drainage holes in
the bottom of the pot, and return it to its location when it
plant is blooming and doing well indoors, you can fertilize it
once a month with a balanced, water-soluble fertilizer such as
Peter’s 20-20-20 or Miracle-Gro. Always follow label directions.
When it comes to fertilizing, more is not necessarily better. If
your plant is spending the winter in a darker, cooler location
where it is dormant, do not bother to fertilize until you move
it outdoors in the spring.
Wait to repot
it until you are ready to move it outdoors for the summer. It
will recover from transplant shock faster when it resumes more
active growth in spring. Although that 10-inch pot sounds small
for a 4-foot tall plant, it also depends on how deep it is.
Remove the pot and check the rootball. If the roots are growing
in a tight circle, your hibiscus is root-bound and should be
moved into a larger container. Avoid the temptation to move it
into a huge pot, though. One or two sizes bigger is sufficient.
If you move a plant from a small pot into a very large one, the
soil volume may hold too much water for too long a time and
cause root rot. Be sure to untangle any circling roots before
placing it into the new container, and prune roots back rather
than coiling them to fit.
You can move your Chinese hibiscus outdoors when all danger of
frost has passed in the spring, right around Memorial Day. Do
not put it out in the full blazing sun right away, though.
Gradually acclimate it to brighter sun over a seven to ten day
period. Move it to a sheltered location such as a porch, or the
filtered shade under a tree. Expose it to direct sun a little
more every day until it is out in full sun for the whole day.
African violet cuttings
Houseplants with Low-E window glass