Continue to plant shrubs, trees, climbers, hedging plants and roses. Avoid planting roses in areas where roses were previously growing, otherwise new introductions may suffer from replant diseases. This occurs when a plant is replaced with the same type. For most plants this does not cause a problem, however, for others, most notably roses and others in the rose family the new plant fails to thrive or put on decent growth. The roots of the previous plant need only to have been in the soil for a few months for the problem to occur.
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.
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.
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.
Place gladioli corms in seed trays or boxes and place in a light, warm (around 10ºC/50ºF) spot 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.
Soft tip cuttings can be taken from fuchsias 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.