The Gardener's Scourge

The leaves of bay and laurels all eaten away around the edges, polyanthus suddenly turn yellow and die. Chances are you have the dreaded vine weevil. It has reached plague proportions in London gardens over recent years.

The adults, which are like tiny black beetles, can only be seen if you go out with a torch at night. Shaking the plants over a sheet will give you a clue to their numbers and give some measure of control. Unfortunately, while the adults disfigure plants biting out notches around the edges of the leaves, it their maggot-like larvae that do the most serious damage, gnawing away at the roots.

Vine weevils are hard to kill because you need to get the adults, the larvae and the eggs. There are two chemicals that will do the job but they are only for use in containers. Provado Vine Weevil Killer 2 (thiacloprid) and Scotts Bug Clear Ultra Vine Weevil Killer (acetamiprid) are both mixed with water. You need to really soak the compost for them to be effective. A single treatment can give up to two months control but my experience suggests that at least one repeat application Let your guard down once and they’ll be back in force.

Never uses these chemicals for any plants you intend to eat. The organic solution is a biological control in the form of a microscopic worm that parasitizes the vine weevil grubs. It works in the garden as well as containers but the soil needs to warm and moist. Putting the worms into action is easy. Just mix some powder into to your watering can and you are away. They work in the garden as well as containers but the soil needs to warm and moist. Google biological pest controls to find suppliers.

Attack of the Greenfly!

Greenfly are amazing creatures. They survive the winter as eggs and during the warmer months they give birth to young greenfly that are already pregnant with a pregnant offspring. Not only that, but they can ride the winds for hundreds of miles to find their way to your window box. The mind boggles. So how do you kill them?

My favorite method is to gently squash them between finger and thumb, taking care not to damage delicate stems. It’s cheap, organic and effective for container plans. An alternative is blast them off with a hose. It won’t kill them all but there will be fatalities. Both these methods require persistence for success.

Insecticides are the next resort. Soft soap, approved by organic growers, contact insectides (containing bifenthrin) kill greenfly and other insects they come in contact with, and systemic insecticides (imidacloprid and thiacloprid) ingested by plant and poison insects that try to eat them. My advice would be to use insecticides sparingly to deal with the first big wave attack. You don’t really want to kill the ladybirds, lacewings, ground beetles and spiders that will eat enough greenfly to prevent them become a further problem once the population is under control.

The sugary droppings from greenfly and other aphids can often be a bigger problem than the direct damage they cause to plants. This becomes covered with a black mould that blocks out light to the leaves. Don’t worry if you see this, the plants are not diseased; they just need to be washed.

Ants farm aphids for their sugar droppings and will viciously defend them against predators. A ring of Vaseline around the base of the plant stem will close down the ants’ access to their herd.

The Facts About Worm Composting

You can buy a worm composting kit and some local authorities even give them away as part of their recycling initiatives. They can work very well but the thing a lot of people don’t realize is that you need to treat the worms as pets. Tiger worms, or brandlings, the type sold for bait in fishing shops, are the ones used for composting.

First thing to know is that they don’t like the cold, which means you can’t leave your bin outside unprotected for the winter. You need to feed them regularly. They like vegetable waste, which is fine if you cook fresh vegetables everyday. They hate oranges. Garden waste is ok in moderation, but if you put lawn clippings in the bin, it is likely to overheat and kill them. Anything that’s a bit woody or has been sprayed is a no, no.

If you feed them right – fresh, little and often – it’s a very nice way to turn your kitchen waste into plant food. Neglect them, overfeed them, let them get too wet, too dry, too cold or too hot and you’ll be left with a bin full of rotting rubbish and dead worms.

Snail Proof Annuals

Many London gardens suffer from plagues of snails and slugs, especially so in the last few wet years. They adore tender young foliage as much as we do – so that’s something we have in common at least!

By painful trial and error I have found that what annuals they will not eat (unless starving)

• Pot marigold (Calendula)
• Poppies – Welsh, field, icelandic, Himalayan etc
• Forget-me-nots
• Annual quaking grass – in fact all grasses.
• Cornflower
• Snapdragons
• Petunias
• Lobelia
• Feverfew
• Foxglove
• Poached egg plant (Limanthes)

Written By Tom O'Leary

Early Bees

As spring approaches, London gets the odd day of sunshine which transforms the city and lightens the step. These warm days have woken the drowsy Bumblebee, a solitary helicopter. It is hard NOT to notice a Bumblebee as it zooms from one rosemary flower to the next – and it set me to thinking; ‘this bee is up too early from his winter sleep, and needs all the pollen he can get’. Having early flowering plants like heather and rosemary in your windowbox will give these early risers a much needed breakfast.

www.bumblebeeconservationtrust.co.uk/

Written By Tom O'Leary