Q. My hibiscus plant, transplanted from a pot to my
outdoor flower bed, is blooming like it should. But the leaves are not getting
any bigger than 1 – 1½” long and ¾” wide. The new leaves also only
get to that size. I water and fertilize if with Miracle Grow regularly, but
that does not help. Any suggestions?
outdoor flower bed, is blooming like it should. But the leaves are not getting
any bigger than 1 – 1½” long and ¾” wide. The new leaves also only
get to that size. I water and fertilize if with Miracle Grow regularly, but
that does not help. Any suggestions?
A. The appearance of plants will be different when grown in
different climate zones. I am now on my farm in the Philippines where we have
Roselle hibiscus (commonly called Red Zinger) growing. I checked the size of
the leaves in response to your email. I normally don’t pay much attention to
leaf size just flower production.
different climate zones. I am now on my farm in the Philippines where we have
Roselle hibiscus (commonly called Red Zinger) growing. I checked the size of
the leaves in response to your email. I normally don’t pay much attention to
leaf size just flower production.
 |
| Roselle growing on our Family Farm in the Philippines |
The
leaves of our Roselle vary in size from the narrowest at about 3 to 4 inches in
length and about 2 inches wide to the largest being 6 to 8 inches long and 4 to
5 inches wide. The largest leaves are growing in partial shade. The smaller
leaves are growing in full sun.
leaves of our Roselle vary in size from the narrowest at about 3 to 4 inches in
length and about 2 inches wide to the largest being 6 to 8 inches long and 4 to
5 inches wide. The largest leaves are growing in partial shade. The smaller
leaves are growing in full sun.
 |
| Tropical hibiscus growing in the Philippines in a tropical climate. |
Appearance
can also be impacted by your management practices. Let’s cover a few of these.
can also be impacted by your management practices. Let’s cover a few of these.
Climate and microclimates. Plants grown under
high light intensities have a different appearance than plants grown under
lower light intensities. The principal differences are in leaf size, color and
thickness.
high light intensities have a different appearance than plants grown under
lower light intensities. The principal differences are in leaf size, color and
thickness.
Leaves
growing under higher light intensities, provided they are getting enough water
and nutrients, will be dark green, smaller, thicker or tougher and develop a
thick waxy coating on the leaf surface.
growing under higher light intensities, provided they are getting enough water
and nutrients, will be dark green, smaller, thicker or tougher and develop a
thick waxy coating on the leaf surface.
The same
plant growing under lower light intensities will have larger and thinner leaves
with a waxy coating that is not as thick. If light intensities get extremely
high then we will see leaf discoloration, yellowing or bronzing, on some plants
because the light intensity is actually damaging the leaves.
plant growing under lower light intensities will have larger and thinner leaves
with a waxy coating that is not as thick. If light intensities get extremely
high then we will see leaf discoloration, yellowing or bronzing, on some plants
because the light intensity is actually damaging the leaves.
 |
| Red hibiscus growing in rock mulch in Las Vegas |
If the
same plant does not receive enough light then the plant will become “leggy”
with large distances between the leaves and thin stems that will not support
its own weight. The plant will become “floppy”.
same plant does not receive enough light then the plant will become “leggy”
with large distances between the leaves and thin stems that will not support
its own weight. The plant will become “floppy”.
Our job as a manager of this plant is to find
a good location in our landscape that provides the right microclimate which
provides enough light for flowering and an appearance close to what we expect.
a good location in our landscape that provides the right microclimate which
provides enough light for flowering and an appearance close to what we expect.
Because
we are in a desert, Hibiscus will not look similar to those grown in semi
tropical or tropical climates but we can approach that look if we are careful
where we plant it.
we are in a desert, Hibiscus will not look similar to those grown in semi
tropical or tropical climates but we can approach that look if we are careful
where we plant it.
Soil. Organic matter such as compost
mixed into the soil at the time of planting and applied annually to the soil
surface surrounding the plant will encourage larger and healthier leaves. I
have seen this numerous times on a number of plants particularly in parts of
the plants that are shaded such as lower leaves.
mixed into the soil at the time of planting and applied annually to the soil
surface surrounding the plant will encourage larger and healthier leaves. I
have seen this numerous times on a number of plants particularly in parts of
the plants that are shaded such as lower leaves.
 |
| Red hibiscus growing in rock mulch in Las Vegas showing signs of leaf drop, leaf yellowing and branch dieback. |
Fertilizer. Fertilizer will influence the
kind of growth. We know that phosphorus fertilizers are very important for
flowering, fruiting, root development and production of oils in plants. If not
enough phosphorus is present it will impact these types of growth.
kind of growth. We know that phosphorus fertilizers are very important for
flowering, fruiting, root development and production of oils in plants. If not
enough phosphorus is present it will impact these types of growth.
We do
not need to apply phosphorus to a soil very often unless it is extremely sandy
or growing in hydroponics.
not need to apply phosphorus to a soil very often unless it is extremely sandy
or growing in hydroponics.
Nitrogen is different. Nitrogen is important for developing dark green
color in leaves and stems and for “pushing” new growth. It is
important in producing good leaf size and in the number of leaves and
supporting stems produced.
Nitrogen
in soil available to plants also dissolves easily in water. Nitrogen is easily does
not dissolve in water easily and is slowly released to plants.
in soil available to plants also dissolves easily in water. Nitrogen is easily does
not dissolve in water easily and is slowly released to plants.
In your
case you want to make sure that nitrogen is applied regularly through the
growing season to maintain dark green color and “push” new growth.
Combined with moderate amounts of shade, nitrogen will encourage more leaves
and larger leaves.
case you want to make sure that nitrogen is applied regularly through the
growing season to maintain dark green color and “push” new growth.
Combined with moderate amounts of shade, nitrogen will encourage more leaves
and larger leaves.
What should you do? Understand that if
your hibiscus is in a very hot, bright location that this location will limit
the plants ability to produce larger leaves. Moderate amounts of shade will
encourage larger leaf development, particularly in a microclimate that gets
morning sun but afternoon shade.
your hibiscus is in a very hot, bright location that this location will limit
the plants ability to produce larger leaves. Moderate amounts of shade will
encourage larger leaf development, particularly in a microclimate that gets
morning sun but afternoon shade.
Apply a
1 inch layer of compost and scratch it into the soil surrounding the plant as
much as you can. When you’re done doing this, apply another 1 inch of compost
to the soil surface and thoroughly wet the soil deeply. Apply a 1 inch layer of
compost to the soil surface every year.
1 inch layer of compost and scratch it into the soil surrounding the plant as
much as you can. When you’re done doing this, apply another 1 inch of compost
to the soil surface and thoroughly wet the soil deeply. Apply a 1 inch layer of
compost to the soil surface every year.
Apply
high nitrogen fertilizer at the beginning of the growing season. Apply a high phosphorus
fertilizer after it is finished blooming. If you apply fertilizers at other
times of the year, apply liquid fertilizers to the leaves.
high nitrogen fertilizer at the beginning of the growing season. Apply a high phosphorus
fertilizer after it is finished blooming. If you apply fertilizers at other
times of the year, apply liquid fertilizers to the leaves.
Do not
apply any nitrogen fertilizers to the soil after August 1 if you are concerned
about winter freezing damage.
apply any nitrogen fertilizers to the soil after August 1 if you are concerned
about winter freezing damage.
I have been able to grow tropical hibiscus from cuttings obtained commercially at the airport in Hawaii, but only with great difficulty. Plants grow well with care but flowers not as large as in Hawaii. Red color grows best, partial shade required, good potting soil.
Direct sun a no-no. In clay pots. Cut down in late fall before frost, but in my unelecrified greenhouse over winter, keeping soil slightly moist. Put in yard in late March early April, protect from wind. It took a number of years before I got the routine down. Now I have about 4 plants 3 to 4 years old, all red, flower regularly. Yellow and orange apparently cannot handle the heat.
But there is neat work around. I found that Rose of Sharon produces flowers that are the spitting image of the tropical hibiscus. I have grown them from commercial seed in the ground, amended local soil, same hard water. Partial shade, handle wind pretty good. Cut down to ground in late fall, grow back in late Spring. My oldest plant, and it is slightly aggressive, makes gorgeous white and another pink flowers. Much easier than tropical. Hope this can help.