December in the garden: Embrace the Structure and Winter Glow

As the days reach their shortest and temperatures settle, the garden enters a period of rest—but not entirely of stillness. While the layers of herbaceous perennials have receded, revealing the bare bones of the landscape, it’s the structure provided by evergreens and hardscaping that truly comes into its own. These elements provide essential stability and form throughout the seasons.

Don’t mistake the cold for a lack of colour! Stepping out on a clear, frosty, sunny day is still a pleasure. The winter garden offers its own unique palette, featuring the vibrant blooms of winter-flowering heathers and the cheerful yellow of Jasminum nudiflorum and Hamamelis mollis. Further colour is supplied by the jewels of the season: the berries of shrubs like Callicarpa and Ilex aquifolium (holly), and the stunning bark of trees such as Betula (birch) and the peeling cinnamon tones of Acer griseum.

Flowers

• Continue to cut back faded herbaceous perennials and add them to the compost heap.
• If the weather remains mild, you can still lift and divide herbaceous perennials. This will increase stocks and revive tired or poorly flowering clumps.
• Root cuttings can be taken now, such as Papaver (perennial poppies), Phlox and Anemones.
• Order seed catalogues, if you have not done so already, to select next year’s bedding and perennial choices.
• Bring forced bulbs into a warm room to encourage them to flower.

Fruit and veg

• Place straw around the base of parsnips to prevent soil freezing, which can make harvesting difficult.
• Winter prune large fruit trees to control their shape and size, and to increase fruiting productivity for next year.
• Plan next year’s crops and order seeds.

Greenhouse

• Pick faded leaves and dead flowers regularly from plants overwintering in the greenhouse, such as pelargoniums.
• Check that greenhouse heaters are working.
• If the weather is mild, ventilate the greenhouse.

Garden maintenance

• Scoop fallen leaves and debris from ponds, leave them on the side so pond life can escape, and then add them to the compost bin.
• Insulate outdoor taps and prevent ponds from freezing.
• Protect terracotta pots from cracking in freezing weather by either bringing them indoors or wrapping them in bubble polythene.
• Raise outdoor patio containers onto feet or bricks to avoid them sitting in the winter wet.
• Rake up fallen leaves in borders that could be harbouring slugs and other pests.
• Clean paths to prevent them from becoming slippery and repair sheds, fences and trellises.
• Avoid walking on lawns covered with frost.

With the autumn-planting season just around the corner, garden centres and on-line retailers are now stocking spring-flowering bulbs. If you want to ensure that you have the variety you’re after, then now is the time to purchase them.

What to look out for
Try to get big, firm bulbs, as usually the larger they are, the better they flower. Avoid any that are soft or have mould growing on.

When to plant spring bulbs?
Autumn is the best time to plant spring bulbs as the soil is still warm. Ideally, bulbs such as daffodils, crocus, muscari and hyacinths should be planted by the end of September if you want them to flower early next year.

 

Tulips should be planted a little later in autumn, so aim to wait until November when the soil is cold and this will help to avoid any potential viruses that may be lurking in the soil.

I often plant tulips in pots as this means that after flowering, when there is just the messy foliage left, they can be replaced by something else to extend the flowering season.

 

 

You can leave planting of Alliums until early in December to ensure that they flower over summer the following year.

 

 

If planting in a border:

• Dig a hole wide and deep enough for your bulbs. Most bulbs should be planted two to three times their depth. For example, for a bulb measuring 5cm high, dig a hole 10-15cm in depth and place the bulb in the bottom of it.
• Ensure that bulbs are placed in the hole with their growing tip facing upwards. If you don’t see a pointy side, look for where the roots are coming out. Sometimes it’s not always obvious, in which case planting them on their side will ensure the shoot grows towards the surface. Space them at least twice the bulb’s own width apart.
• Cover with soil and gently firm in.
• If the ground is moist there is no need to water, otherwise water straight after planting.
• Squirrels often love to dig up freshly planted bulbs. If you think this may be a problem, weigh down some chicken wire over the area to protect the bulbs.

Planting in a container:

• Use a mix of three parts multi-purpose compost with one part grit as this will help with drainage.
• Before planting, check that the bulbs are healthy and showing no signs of rot. Plant the bulbs three times their depth and one bulb width apart.
• Water after planting, ensuring that they don’t dry out. Once you start to see active growth, ensure that they are regularly watered. It will also help at this stage that you start to feed them with a liquid tomato feed. Once they have finished flowering and the foliage begins to die back, stop feeding.

If you find that after buying your bulbs, you forget about them or haven’t had the time to plant them, don’t worry too much. Plant them as soon as you remember. I’ve planted Alliums in late January some years, they will still flower but perhaps just a little later than expected.