DULWICH STORIES:

Spring in the garden

Local arborist John Welton offers tips for reversing the decline of biodiversity in the garden.

Local arborist John Welton

Make a positive contribution to slowing climate change and help reverse the decline in biodiversity. Here are a few ideas.

Mulch

Spread natural soil-improving layers on your borders, for example composted leaves or woodchip. It needs a depth of 2-3 inches. Established plants will growth through this but weed seed growth will be suppressed. It helps retain moisture during dry spells, gives protection against late frost damage and feeds the soil and beneficial worms over the longer term giving your garden extra resilience.

Let your lawn flower

Spring flowers will emerge if you stop mowing your lawn for a few weeks in Spring and the insects will get all the benefits when other flowers may be in shorter supply.
Make a wood pile
This can be a natural feature in a shady place in the garden and provide a habitat for a huge amount of insects and a protected feeding place for frogs, newts and toads.

Leave old stumps intact

You will be amazed at the amount of life decaying wood supports, for example the rare stag beetle larvae. They live for around 7 years before emerging as scary-looking but wonderful beetles. These beetles only survive in the south east.

Insect-friendly plants

Try and increase the number of plants with flowers suitable for insects. Avoid plants with double or multi-petals flowers.

Winter

Local arborist John Welton urges garden shelter for birds during the winter months

Long cold, wet and windy nights mean our native resident birds need garden shelter as they have nowhere else to go. It is so easy to forget them, but they are still in our garden, sleeping in protected places to survive.

Avoid winter tidy-ups of reducing shrubs, to ensure the very best night-time shelter for these birds. Wrens, thrushes and blue tits shelter in evergreen climbers in your garden like ivy, also honeysuckle, clematis armandii, climbing hydrangea, solanum and trachelospermum. Residual heat provided by walls and leaves are life-saving.

Bird boxes on the house wall or on outbuildings or in trees also provides valuable overnight shelter at this time of year.

Bird boxes on the house wall or on outbuildings or in trees also provides valuable overnight shelter at this time of year. Small birds that are more vulnerable like wrens and blue tits often come together to roost in nest boxes with amazing numbers - up to 60 wrens have been recorded in a box. Bird boxes serve an important dual purpose - winter retreat and spring nesting.

We are probably all aware of the increase in noisy parakeets - but the serious danger is the food sources they take from our native birds and their domination of highly sought-after tree nesting holes and cavities. We can all help. Leave out bird food, put up some bird boxes and stop tidying.

Autumn

The ground is still warm. New tree roots are active for a few weeks yet, allowing them to establish with the surrounding soil. This means a healthier, more resilient tree next year.

Trees are essential to our environment. They absorb carbon dioxide, reflect heat upwards and so provide cooling effect. They host complex microhabitats for insects, lichen and fungi, as well as a valuable food source for a wide variety of birds. And they absorb airborne pollutants, reduce noise and provide screening.

Right tree for the right space

Consider the available space and the potential size of tree in 10 years, existing neighbouring trees, seasonal interest preferences (for example spring flowering, bark colour/texture) and what wildlife can be supported. Native species are often the best performers in this area.

Dig a planting hole twice the width and only slightly deeper than the container the tree is in. Remove clay or larger stones. Loosen the bottom of the hole to help drainage. Make sure the rootball is positioned in the hole with its surface level with the surrounding soil and the tree is perfectly upright. Compost/mycorrhizal root can be mixed with backfill to improve soil before refilling around the rootball and firming in to remove air pockets. Mulching around the base of the tree with compost and woodchip will help prevent weed, retain moisture, insulate from heat and cold and improve soil in the longer term. Larger trees should be staked to stabilise roots and aid establishment. Water with about 20-30 litres of water to settle the root ball in place.

Rowan (sorbus aucuparia) - spring white flowers, orange autumn fruits and leaf colour.

5 favourite smaller species

I recommend these for wildlife biodiversity and interest:

  • Rowan (sorbus aucuparia) - spring white flowers, orange autumn fruits and leaf colour.
  • Hawthorn (crataegus monogyna) - white spring flowers and red autumn berries with leaf colour.
  • Bird Cherry (prunus padus) - white racemes of almond scented flowers.
  • Cornelian Cherry (cornus mas) - tiny yellow flowers before leaves in February and fruits in August.
  • Cotoneaster Lacteus - evergreen small tree or large shrub with flowers in spring and masses of berries in autumn.