Azalea mollis - Azalea molle - are a wide ranging group of deciduous azaleas
that originated from Belgian and Dutch sources, being hybrids between
the Azalea molle and A. m subsp. japonicum.
there have been many other hybridizations - notably the English
hybrids as typified by the Knap Hill hybrids and also the Exbury hybrid
deciduous azaleas. Ghent hybrids will also fall into this group.
We make no apologies for listing these as Azaleas - rather than the
botanically correct Rhododendrons - for they are universally known
amongst gardeners as Azaleas.
These deciduous Azaleas have complex hybrid ancestry. Ghent Hybrids -
were bred in Belgium for which we give thanks. Further hybridization was
carried out at Knap Hill, and those are naturally classified as Knap
Hill or Exbury Hybrids.
my close encounters of both types, I have always found the Knap Hill or Exbury
hybrids to have the better scent - especially in the yellows and lighter
All of the images on this page are from deciduous Azaleas raised
from a single packet of Azalea Knap Hill/Exbury hybrids many years ago, at
Great Comp Garden
in Kent UK. Many of the Knap Hill hybrids have gorgeous scent, unlike the true
Azalea mollis, which seem to have no or little fragrance. That from the
experience of being up close to take photographs!
The image on the left shows the wide range of autumn
foliage colour that is to be seen on mass plantings of the deciduous
Azalea. So we get two good seasons of colour - early summer for the
flowers and autumn for the foliage.
The flowers are typically funnel shaped, and long lasting. The
lighter coloured flowers seem to generally have the best scent - especially the
yellows. As well as having a huge range of flower colours, Azalea mollis
hybrids have a fantastic range of
autumn - Fall - colours as the leaves prepare
for winter. ( All the above Azaleas were growing on the edge of woodland paths,
with access to good light and sunshine.)
Growing Conditions - Care of Deciduous Azaleas/
Like all members of the Azalea family, Azalea mollis are best
grown in acid soils. Either naturally humus rich soils, such as would be
the case in semi woodland situations or with an added
every autumn. They are not happy in waterlogged conditions, and
fare best if in well drained soil.
Deciduous Azaleas are tolerant of semi shaded positions, but are at
their best if planted in full sun. This probably allows the wood to
ripen for producing the best flowering display for the following spring
Frosts are not so damaging to Azalea mollis types as with
the evergreen azaleas. This is largely due to the fact that they are
later flowering - normally May or even June. Thus the opening buds are
not normally affected by late frosts. Togther with that, this group is
fully hardy for garden use.
Container Growing This group of Azaleas
are well suited to being grown in patio pot situations. Keep the pot
shaded from the hottest of suns, and give sheltered situation in severe
winter to avoid the possibility of the pot compost freezing.
Azalea mollis varieties can easily reach 8ft (2.4m height). Advice on
how to Prune Azaleas
The most important thing being the dead-heading of the faded flowers to allow
for good growth of next season's flower buds. It takes a lot of plant energy to
set seed, so the dead heading will help to maintain a healthy and vigorous
Propagating Deciduous Azaleas.
Seed Propagation Azalea mollis and related hybrids
readily set seed which should be collected as soon as ripe - just before
the seed pod open/burst. The seed con be sown on the surface of a peat
compost - or just peat will a little sand added - as soon as the seed is
collected. If you have a solitary plant, then there is a reasonable
chance that the new seedlings will resemble the parent. In practice,
there will be many different forms as to flower and growth habit.
Cuttings of Deciduous Azaleas are best done with
semi ripe cuttings in
mid summer. Whilst they are relatively easy to root, they will need cold
house or cold frame protection through the first winter - potting them
up in early spring. Alternatively these Azaleas can be propagated from
layers - either by pegging a supple low growth onto the ground, or by
Problems with Azalea Mollis - Deciduous Azaleas.
Insect Pests Azalea molle types are relatively trouble
free as far as insect pests are concerned, though you might find signs
vine weevil damage on the foliage. Container grown plants might fail
if there are vine weevil larvae in the compost. Whitefly is sometimes
(rarely) a minor problem.
Diseases include Honey Fungus (rarely) Powdery Mildew
on the foliage which can severely affect the flowering capabilities for
the following spring, and sometimes rust on the leaves. The latter is
rarely a problem of any magnitude.
Feeding and Fertilizer.
In open ground situations, with regular mulches, the only feed normally
required would be a dressing of bonemeal in early spring - or blood fish
and bone. Osmocote could be the alternative for a slow release
fertiliser throughout the growing season. Osmocote would be the
preferred choice for container grown plants.
Yellowing of the Leaves
This is usually a sign of lime in the soil - it only needs to be
slightly alkaline to bring about this chlorosis. An annual dressing of
iron based feed/treatment will usually do the trick. It may be that if
the azalea is growing in pot container, the tap water used for watering
may be from a limestone area!