Deadhead Hippeastrum (amaryllis)
leaving the flower stalk(s) to die down naturally. Keep feeding and
watering and you may be treated to further flowers in August as well as
the normal blooms next winter.
Schlumbergera truncata and S. x
buckleyi (Christmas cactus) - twist off some of the stem segment,
with a view to keeping a balanced shape to the plant. This will
encourage bushy growth. The detached segments can be used as cuttings,
if dried and kept warm for a week, before potting up in gritty compost.
Stand houseplants on trays of damp gravel to counteract drop in
humidity in centrally-heated homes.
Water houseplants sparingly until they come into active growth with
the advancing spring.
If the leaves on pot Cyclamen
start to turn yellow this may be a sign of overwatering. Keep
Cyclamen in a cool, well-lit
place and water them from below (into the saucer). Allow the plant to
drink for half an hour, before pouring away the remaining water left in
the saucer. If the level in the saucer does not go down, then the plant
did not need a drink. You can always tip out the rootball and feel it
before watering, to see if the compost is dry, or if it is still moist
from previous watering.
Maintain a minimum of 5°C (42°F) to prevent
Fuchsia,
Pelargonium and other tender
plants being killed by the cold. Higher temperatures (at least
12°C/54°F) will be needed for tropical plants.
Fuchsias can be started into active growth (if not done last month)
by repotting, increasing watering, feeding (with a slow-release
fertiliser such as blood, fish and bone), and putting them in a sunny
place. Those that were started up in January can now be sprayed with
water occasionally to raise humidity, encourage growth, and help bud
break.
Soft tip cuttings can be taken from fuchsias this month.
Don't leave houseplants on windowsills behind the curtains on frosty
nights, especially if your windows are not double-glazed.
On sunny days, ventilate the glasshouse or conservatory, to reduce
the risk of fungal infections.
Prune conservatory climbers towards the end of the month:
Plumbago, passion flower and
jasmine can be thinned out, so that they have a neat framework of
branches. The previous year’s growth can also be cut back to two or
three buds from the main framework, to keep the size under control.
Bougainvillea pruning is
sometimes left until early spring the year after flowering, because of
the risk of frost damage when pruning in the autumn, just after
flowering. Last year’s growth should be spur-pruned back to 2.5cm (1in)
of the main woody framework. Do not prune unless the glasshouse or
conservatory is reliably above 10°C (50°F).
Cut back leggy Hypoestes
(polka dot plant), Pilea
(aluminium plant), Coleus (now
called Solenostenum),
Tradescantia,
Pelargonium,
Salvia,
Argyranthemum and
Lantana to encourage new growth
and keep the plants well shaped. Prunings can always be used as softwood
cuttings.
Citrus trees in pots should be top-dressed with fresh compost, and/or
repotted if necessary.
Greenhouse bulbs that have finished flowering (e.g. freesias and
Lachenalia) can now be fed weekly
with high potassium feed (such as tomato fertiliser), to build up the
bulbs before resting them over the summer. Reduce feeding and watering
as the foliage starts to die back, and then lay the pots on their sides
under the greenhouse bench until next autumn.
Lily-of-the-valley (Convallaria)
that was lifted from the garden to use as winter-flowering pot plants in
the greenhouse, should now be planted back outside.
Begonia,
Gloxinia and
Achimenes tubers can all be
planted this month. Begonias and gloxinias need to be planted hollow
side upwards; Achimenes can be
planted on their sides, in trays if necessary, before potting them on as
necessary once growth appears.
Cool conditions and regular watering will help keep potted indoor
azaleas looking good for longer. Remember to water azaleas with
rainwater collected in a rain butt, not with tap water.
Check that light levels are sufficient for houseplants. They will
need light to carry on until the spring, and can easily be forgotten in
a back or spare room that receives little natural light, or with the
curtains left drawn. They are best moved to sunny positions until March.
If you do have any seedlings and/or cuttings in the greenhouse, make
sure they are getting the maximum light available, or else they will
become weak and leggy. If necessary, turn them once a day so that they
get light on both sides. This will stop them leaning over towards the
light, and keep them upright and compact.
Don’t forget to prick out seedlings before they get too crowded, and
then to pot them on as individual transplants as soon as they are large
enough.
Plug plants are now available for sale. They can be grown on in your
glasshouse, being a relatively cheap source of large numbers of plants,
while avoiding the need for propagation facilities and labour.
Cacti and Clivia houseplants
should still be kept dormant until March. Very little water (barely
moist) and no feeding is advised until then.
Clivia will additionally benefit
from lower light levels (e.g. a back room where the lights are never
turned on and there is not too much natural light) - this will improve
flowering in the following season.
Regularly pick over plants and sweep up fallen debris, to prevent
disease spreading.
Check that glasshouse heaters are functioning properly, by investing
in a maximum-minimum thermometer to enable accurate monitoring of your
greenhouse temperature.
Check your glasshouse insulation is still secure for the remainder of
the cold weather.
Clear leaves and twigs from guttering on greenhouses and sheds.
Keep alpine houses well ventilated.
Indoor forced bulbs that were in the house for winter displays, but
which have now finished flowering, can be left outside in a sheltered
spot in the garden to finish dying down.
Pest & disease watch
Pick up dead fallen leaves to deter
Botrytis (grey mould).
Ventilating the glasshouse or conservatory on mild sunny days will
help to reduce fungal infections.
Cyclamen persicum (often given
as a winter pot plant) is best watered from below (i.e. into the saucer,
not the pot), as wetting the leaves can easily result in fungal
infections such as cyclamen grey mould and rotting off.
Unhealthy looking Cyclamen may
also be suffering from vine weevil attack, so gently knock the plant out
of the pot to check the roots for signs of larvae and treat accordingly.
Look out for damping off disease on any seedlings, and treat
appropriately.
Keep an eye out for overwintering pests such as whitefly or red
spider mite and treat accordingly. Nooks and crannies, and the bark of
woody houseplants and vines, can harbour nymphs of mealybugs and scale
insects.