News

Flowers

Pelargonium 'Magic Lantern'Sowing and planting

Sow seeds of BegoniaLobeliaSalvia and Pelargonium in a heated greenhouse or propagator to provide early plants.

Sweet peas can be sown this month. Sweet peas sown earlier in the autumn can now be potted on taking care not to disturb the roots too much. Place them on a sunny windowsill, or on a high shelf in the greenhouse that gets plenty of light.

This is the last chance to sow seeds that need frost in order to germinate (such as native tree and shrub seeds, and alpine plants).

Plant lily bulbs in pots and in borders during mild spells.

Summer bulbsseed potatoes and onion sets will be available to buy from the middle of the month.
 


Iris unguicularis 'Mary Barnard'Cutting back, pruning and dividing

Cut off old leaves of hellebores that produce flowers from ground level to expose the flowers.

Cut away some Iris unguicularis leaves to expose the flowers.

Root cuttings can be taken now. Papaver (perennial poppies), Verbascum (mullein), Acanthus and Phlox are suitable examples.

Start cutting back grasses and other perennials left for winter interest. Alternatively you can leave them a few more months to provide cover for wildlife.

In mild areas, and during dry spells, you can still lift and divide herbaceous perennials. This will increase stocks, and revive tired or poorly flowering clumps.
 


General maintenance

Rake up any winter debris and leaves off your borders to keep them tidy. Clear up any weedy beds ready for mulching in the spring.

Collect leaves that have blown over alpine beds as these plants are easily smothered. Bare patches can be covered with gritty compost.

container maintenance

Containers

Keep tubs and containers tidy, cutting back and removing debris regularly. They can be mulched with compost or grit. Grit is aesthetically pleasing, and will reduce the surface puddling that can occur when light composts are beaten into a solid ‘cap’ by raindrops.

Some pots - particularly those sheltered by eaves or balconies - may need watering. Check the compost (at a hand’s depth) to see if it feels dry. Aim to keep pots moist (not too wet), but do not let them dry out.

Raise patio containers onto feet or bricks, if you have not done so already, to avoid them sitting in the wet.

Tender plant care

Even in mild areas, tender plants that cannot be left outside with protection should really be taken into the greenhouse or conservatory by the beginning of this month. In cold areas, you are best moving things inside much earlier, in the autumn.

In cold spells, protect non frost-proof containers (terracotta pots for example) with bubble wrap, hessian or fleece, to prevent them cracking. Grouping the pots close to a south-facing wall may provide additional protection to the most vulnerable ones

Ensure protective straw or fleece is still in place on tender plants overwintering outdoors.
 


shopping for seedPlanning ahead

Order catalogues for spring planting of summer-flowering bulbs, bedding and herbaceous perennials.

Members can order seed from the RHS Seed Scheme between 1 November and 31 March.

Stock up on store cupboard items such as string, stakes and canes for use later in the year.
 


healthy dahlia tuberPests and disease watch

Inspect stored tubers of plants such as Dahlia and Canna for signs of drying out. Although care is needed to prevent dampness and rots occurring, it is important not to let the tubers become bone dry, or they will not grow next season.

Keep alpine houses well ventilated. Remove dead leaves from around basal rosettes to prevent rotting.

Protect new sweet pea plants from aphids. Check autumn-sown sweet peas growing in cold frames, and apply mouse and slug controls if necessary.

hellebore leaf spotWatch out for downy mildew and black spot on winter pansies. Remove any infected leaves and destroy badly affected plants.

Look out for rots such as: crown rot, sclerotiniaDelphinium black blotch and black root rot on died down perennials. Check stored bulbs for signs of rot and remove affected bulbs.

Be aware that many diseases will overwinter in the soil, or on plant debris. Antirrhinum rust and Delphinium black blotch, as well as sclerotinia, will lay dormant and re-infect plants when they come up the following year. It may be necessary to replant new specimens in another place if the problem is severe.

Hellebore leaf spot can be a problem on old foliage of hellebores.

Ponds

pond iceGeneral maintenance

Monitor the water level of your pond, as hard frosts can cause defects in the liner and in concrete structures. If the water level drops considerably, then it may have developed a leak. Be sure to keep it topped up until repairs can be carried out in the spring.

Rake out fallen leaves or shake off those that have gathered on protective netting.


Troubleshooting

If necessary, use pond heaters or place floats on the surface of the water to keep it from freezing over as this can be fatal for fish and other pond life. To make a hole in frozen ponds, hold a saucepan of hot water on the surface until melted through. Do not crack the ice, as this is harmful to fish.

Structures

hardwood benchMaintenance

In dry spells, you can treat timber structures, including garden furniture, with wood preservative and stain. Only do this in a well-ventilated space, to reduce the risks to your lungs and eyes. Make sure you use appropriate products - creosote (for example) is no longer legal.

Check and repair pergolas and arches if needed.

Wash out your old pots; use a product such as Citrox, to reduce bacterial and fungal spores without causing toxicity to plants.


under tree lighting in winterPipework and power

Now is a good time to consider installing garden lighting, lights and power points to sheds and outhouses, so that you can garden on wet days and in the evenings.

Install drainage and water pipes.

Ensure all stand pipes and irrigation lines are drained to avoid damage from water freezing in them. Put lagging around outdoor taps to prevent freezing and to enable use throughout the winter.
 


country style gravel and stone pathPaths and projects

Garden contractors are often short of work in winter and therefore available to do major tasks such as paving, fence building and pond digging.

Take action to remove algae from paths if they start to become slippery, beware of using too much salt as this could damage your plants.

Make a cold frame as a winter DIY project - you can save lots of money, as good cold frames are very expensive to buy.

Greenhouse, conservatory and houseplants

Hypoestes phyllostachyaHouseplant care

Check that light levels are sufficient for houseplants. They will need light to carry on over the winter, 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 windowsill until March. Don't leave houseplants on windowsills behind the curtains on frosty nights, especially if your windows are not double glazed.

Water houseplants sparingly. Most should be barely moist in winter.

Cut back leggy Hypoestes (polka dot plant), Pilea (aluminium plant), Solenostemon (coleus) and Tradescantia to encourage new growth.

Pelargonium 'Pink Champagne'Maintain a minimum of 5°C (41°F) to prevent FuchsiaPelargonium and other tender plants being killed by the cold. Higher temperatures will be needed for tropical plants.

Fuchsias can be started into active growth by re-potting, increasing watering, feeding (with a slow-release fertiliser such as fish blood and bone), and putting them in a sunny place.

Clivia benefit similarly from a dormant period over winter, with less watering, feeding, and lower light levels.

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.


Narcissus papyraceus 'Ziva'Bulbs and corms

Indoor forced bulbs used for Christmas displays, and which have now finished flowering, can be left outside in a sheltered spot in the garden, to finish dying down.

Support bulb flower spikes with canes (if necessary).

Pot up Hippeastrum (amaryllis) bulbs, and bring them into active growth with regular watering and feeding. They should give you beautiful flowers for the late winter/early spring.

Place hyacinths in a cool, bright place in the home. If it's too warm, the leaves will elongate and the flowers will fade quickly.

Cyclamen persicum appreciates a cool room with good light. If leaves on cyclamen start to turn yellow, this may be a sign of overwatering. Water from below (into the saucer), and allow the plant to drink for up to half an hour before pouring away the excess water left in the saucer - wetting the leaves can easily result in fungal infections and rotting off.
 


cacti collectionCacti

Remember that cacti need very little water, and no feeding, over the winter. Keep them barely moist until the spring, when they will be coming up to flowering and will therefore appreciate extra water and feed.


Encourage bushy growth on Christmas cacti (Schlumbergera truncata and S. x buckleyi) by twisting off outer segments from the most vigorous shoots after flowering. These can be used as cuttings if dried and kept warm for a week before potting up.

If your Christmas cactus (Schlumbergera truncata and S. x buckleyi) failed to set flower buds, it may be that the temperature is too high (above 18°C or 65°F), or that the plant is receiving light from an artificial light source after dark. Try moving the cactus into cooler conditions or away from night lighting.
 


sweeping snow from greenhouseIn the greenhouse

Check that greenhouse heaters are functioning properly, by investing in a maximum-minimum thermometer to enable accurate monitoring of greenhouse temperatures.

Check your greenhouse insulation to make sure it is still secure.

Remove snow from greenhouse and conservatory roofs, to prevent damage and to allow good light penetration.

Clear leaves and twigs from guttering on greenhouses and sheds.

Ventilating the greenhouse on mild sunny days will help to reduce fungal infections.


mealy bugPest and disease watch

Regularly pick over plants and sweep up fallen debris, to prevent disease appearing and spreading.

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 mealybugs and scale insect nymphs.

Look out for cyclamen grey mould.

This is a good time to clean all your old pots and seed trays, so that they are ready for next spring’s flurry of activity. Thorough cleaning will reduce pest and disease problems, and will reduce your propagation and sowing problems. A Citrox solution will clean well, without unpleasant odour or toxicity to plants.