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Flowers

Sowing and planting

Lily 'Sensation'Lily bulbs can be planted in pots, for flowers this summer. After growing on indoors or in a cool greenhouse, they can be moved onto the patio when in flower, so that you can enjoy the blooms.

Dahlia tubers stored over winter (or bought this year) can be started into growth. Place them in a light, warm place to sprout before planting. They will need additional misting with a spray-bottle of water, to stop them drying out.

Bulbs coming up in the rock garden or in containers may benefit from overhead protection from the rain and snow. A sheet of glass or Perspex placed on piles of bricks will do the job.

Hardy annuals can be sown in pots or modules to provide colour.

Summer-flowering Dutch iris bulbs can be forced and used as cut flowers.

Place gladioli corms in seed trays or boxes and place in a light, warm spot around 10ºC (50ºF) to encourage them to sprout before planting. This will ensure an earlier display.

Sweet peas can be sown under cloches, in a cold frame, or in a cool room in the house. Any sweet peas that were sown earlier in the autumn can now be potted.

Root cuttings can be taken of Papaver (perennial poppies), Verbascum (mullein), Acanthus (bear’s britches) and Phlox.

Check on tender plants overwintering outdoors to ensure protective coverings are still in place.
 


Miscanthus sinensis 'Grosse Fontane'Cutting back, pruning and dividing

Cut back deciduous ornamental grasses such as Miscanthus and other perennials left for winter interest.

Continue to deadhead winter pansies and other winter bedding. Pansies will carry on into the spring and even to early summer, if attended to frequently.

Cut off old leaves of hellebores that produce flowers from ground level (including Helleborus x hybridus and H. niger) to expose the flowers and remove possible foliar diseases such as hellebore leaf spot.

At the end of the month prune back the stems of pot-grown fuchsias, which are overwintering under cover, and place in a well-lit, warm place to encourage new growth.

Divide and/or plant bulbs-in-the-green such as snowdrops (Galanthus) and winter aconites (Eranthis hyemalis).

Divide clumps of herbaceous perennials that you want to propagate, those that have become too large for their allotted space, and those that are flowering poorly or have lost their shape.
 


add mulchGeneral maintenance - soil

 

Prepare beds for new roses when conditions allow. Avoid wet days and frozen ground.

Test your soil for pH and nutrient levels; this can help you choose suitable plants for your garden, and allow you to rectify any nutrient deficiencies with a spring feed. Simple tests can be done at home (see left), and the RHS also offers a soil analysis service.

Improve the drainage of heavy soils by working in lots of organic matter and coarse gravel (if necessary).

Clear up weedy beds before mulching.

Mulching with a deep layer of organic matter helps to condition the soil, suppress weed growth, insulate plant roots from temperature fluctuations, and conserve soil moisture during the summer. Lighter soils can be mulched now, but heavier soils are best left until March, when the soil is warmer.

Towards the end of the month, you can top dress beds and borders with a balanced fertiliser such as Growmore or blood, fish and bone, to feed perennials as they start back into growth.
 


container maintenanceGeneral maintenance - containers

Check whether containers need watering. Pots that are sheltered by eaves or balconies can miss out on any rainfall. Check the compost at a hand’s depth to see if it feels dry. Aim to keep pots moist, not wet.


Pots and containers benefit from topping up with fresh John Innes compost. Old compost can be removed and replaced if there is not much room.
 


Saxifraga 'Schleicheri'Pest and disease watch

Remove dead leaves from around the basal rosettes of alpine plants such as saxifrages to prevent rotting.

Top dress spring-flowering alpineswith grit or gravel to show off the plants and to help prevent stem rots.

Snowdrops can be vulnerable to botrytis (grey mould).

On winter pansies watch out for downy mildew and black spot.  Remove any infected leaves and destroy badly affected plants. To avoid the build-up of diseases, do not to plant pansies in the same place every year.

Look out for rots (such as crown rot, sclerotiniadelphinium black blotchphytophthora root rot and antirrhinum rust) on emerging perennials and shrubs.

Hellebore leaf spot can be a problem on old foliage of hellebores. Cutting back the old leaves should control the problem, and allow the flowers and new growth to be better seen.

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

Protect lily, delphinium and hosta shoots from slugs and snails before they appear.

Inspect stored tubers of plants such as dahlia and canna for signs of drying out. Do not let them become bone dry or they will desiccate; but too wet and they may rot.
 


RHS seed schemePlanning ahead

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

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

Stock up on stakes and ties for the coming season, if you have not done so already.

Plan your summer bedding and container planting schemes in good time for ordering the necessary bulbs, annuals and seed, and for propagating the relevant material.

Ponds

pond profileYou could take the opportunity to dig a new pond - the spring rains may help to fill it. We recommend a minimum depth of 60cm (2ft) at the deepest point, to reduce the risk of the pond freezing to its full depth.

Gently sloping contours between the shallow and deep areas, and between the bank and the water, are more wildlife-friendly, and help to make marginal plantings appear natural.


Troubleshooting

Grille coverings (either simple meshes or bespoke features) can protect young children from accidents. The size of the mesh can be judged in order to prevent hazard, but to also allow access for wildlife, and to preserve the aesthetic charm of the pond.

Structures

algae on brick pathMaintenance

Take action to remove algae from paths if they start to become slippery.

Gently remove snow from glasshouses and conservatories to prevent damage to the glass and allow good light penetration.

Go through your shed and remove any old, out-of-date garden chemicals. If in doubt of how to dispose of them, your local authority tip should be able to help. You can check our list of chemicals removed from the market for up-to-date information.
 


wooden pergolaRepair

Check and repair pergolas and arches if needed.

Rub down and treat wooden garden furniture when dry. Only use paints and preservatives in a well-ventilated area.

In dry spells, you can treat timber structures 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.
 


new fencing with gateNew projects

Put design ideas for new garden projects on paper and cost them out. This month is your last opportunity to see the bare skeleton of your garden before all the perennials and new leaves emerge. Hard landscaping has less impact on plants when they are still dormant. But do take care not to compact your soil with machinery when it is wet.

Garden contractors are likely to be less busy before March, and may therefore be available for major jobs such as paving, fence building and pond digging.

Make a coldframe - you could save lots of money, as good cold frames are very expensive to buy.

Greenhouse, conservatory and houseplants

Clivia miniataHouseplants

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 rarely turned on and there is not too much natural light) - this will improve flowering for the following season.

Deadhead Hippeastrum (amaryllis) leaving the flower stalk 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.

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. If the leaves on pot Cyclamen start to turn yellow this may be a sign of overwatering.

Citrus trees in pots should be top-dressed with fresh compost, and/or repotted if necessary.

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.

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.
 


 

General houseplant care

  • group of houseplantsDon't leave houseplants on windowsills behind the curtains on frosty nights, especially if your windows are not double-glazed.

  • 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.
  • 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.
     

Jasminum officinale 'Devon Cream'Pruning and training

Plumbagopassion flower and jasminecan 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).

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.

Cut back leggy Hypoestes (polka dot plant)Pilea (aluminium plant)Coleus(now called Solenostenum), TradescantiaPelargoniumSalviaArgyranthemumand Lantana to encourage new growth and keep the plants well shaped. Prunings can always be used as softwood cuttings.
 


Fuchsia 'Dollar Prinzessin'In the greenhouse

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.

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.

BegoniaGloxinia 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.

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.
 


General greenhouse tasks

greenhouse ventilation

  • Maintain a minimum of 5°C (42°F) to prevent FuchsiaPelargonium and other tender plants being killed by the cold. Higher temperatures (at least 12°C/54°F) will be needed for tropical plants.
  • 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.
  • On sunny days, ventilate the glasshouse or conservatory, to reduce the risk of fungal infections.
  • Keep alpine houses well ventilated.

soft wood cuttingsPropagation

Take fuchsia cuttings from the soft tips this month.

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.
 


Pest and disease watch

grey mould on pelargoniumFungal diseases

Ventilating the glasshouse or conservatory on mild sunny days will help to reduce fungal infections.

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

Pick up dead fallen leaves to deter Botrytis (grey mould).

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.

Look out for damping off disease on any seedlings, and treat appropriately.
 

vine weevil grub on cyclamenPests

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.

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.