Hydrangeas
Arborescens
(aka Smooth Hydrangea)
The
"wild hydrangea," as it is sometimes called, grows abundantly
in its native forests of the eastern U.S. where it thrives on
the banks of streams and on rocky slopes and in the shady, moist
undergrowth. It is not often seen in gardens although it is easy
to transplant. However, large pom pom varieties, notably "Annabelle"
and "Grandiflora" are very popular and often rival the
beauty of the macrophyllas when in bloom.
Unlike the
macrophyllas, the hydrangeas in this group are hardier, blooming
on new wood and have a suckering habit. The leaves are ovate,
not as thick as macrophylla and are colored differently on the
underside of the leaf (either white or gray depending on the sub
species).
Culture
Hydrangeas
are moisture loving plants and will languish in hard soils and
full sun. They will flourish in moist, well-drained soils that
have been enriched with organic materials. Watering is necessary
especially in periods of drought. Plants will wilt when they need
watering. Be aware though, that they will also wilt during extreme
hot periods even after they have been watered. They will perk
back up after the temperatures have cooled in the evening.
Site
Selection - "Annabelle" benefits from part
sun and shade. Morning or late sun is best with shade provided
during the hottest part of the day. Although you can grow it in
full shade, blooming will be better with some sun. Northern gardeners
can grow this variety in full sun.
Planting
- Dig a generous hole, wider than the root ball and add compost,
aged manure, leaves, peat moss, etc. to the planting mix. Position
the plant so that an inch of the root ball sits above the soil
line, fill in with your native soil that has been amended and
water well. Surround the plant with 1-2 inches of mulch - leaves
and pine needles are excellent choices.
Fertilizing
- should be done twice yearly - in late winter or early spring
and then again after flowering in late summer. Do not fertilize
after August. I use a general 10-10-10 granular fertilizer which
I sprinkle around the base of each plant. Liquid fertilizers can
also be used and are especially recommended if your plant is suffering
from chlorosis (yellowing leaves). Always follow the rules on
the fertilizer label and don't over-do it. Too much fertilizer
can be harmful and can result in excessive green growth and fewer
flowers.
Pruning
- Unlike the macrophyllas, the hydrangeas in this group bloom
on new wood. So you can cut it back to within one foot of the
ground in fall or early spring. Severe pruning done this way will
result in larger blooms which sometimes can be a problem because
they are difficult to support and flop over after a rain. If you
prefer smaller blooms, don't prune the shrub back so drastically.
Either way you prune, you can count on blooms.
Keep
in mind that the various types of hydrangeas are pruned differently!
(For pruning instructions for oakleaf,
panicle, and macrophylla
hydrangeas, consult the appropriate web pages on this site).
Hardiness
These are
the most hardy of hydrangeas and will survive up to zone 3. Click
here for the USDA Plant Hardiness Zone Map.
Cultivar
List
Name |
Flower
Type |
Characteristics |
Close-Up
View |
Full
View |
Annabelle
|
Mophead |
Very
large blooms, up to 10" across. They start out a pale
green before turning to white. |
|
|
