What to do in the garden in April
26 April 2010Ponds
If frogs didn’t return to your pond to breed in March then they should certainly do so this month, leaving numerous clumps of spawn – eggs surrounded by a protective jelly. Newts (the smooth newt Triturus vulgaris is the only species found in Northern Ireland - which removes any problems of identification!) will also emerge from hibernation and find their way back to a pond and it’s worth venturing out at night with a torch to see them courting. The crest of the male becomes more pronounced in the spring as does the orange colour on his belly. He will swim round a female, nudging her with his head and lashing his tail around.
Common newt spawn is far less obvious than that of frogs as newts lay single eggs on the under surface leaves of water plants, wrapping each one carefully to protect it against possible predators. This is a vast amount of work as the female lays about a dozen eggs a day and maintains this rate of egg production for about three weeks.
If you have swallows in the area, try to ensure there is mud around the edge of your pond. With luck, the birds may settle to collect this to help with their nest construction.
Attractive plants for the margins of your pond which come into flower this month include marsh marigold Caltha palustris and lady’s-smock Cardamine pratensis, also known as milkmaids and fairy flower. Its most popular name, however, is probably cuckooflower, as its first flowering coincides with the arrival in Britain of the cuckoo. Cuckooflower is one of the food plants of the caterpillar of the orange tip butterfly, which is why this insect is often seen in damp areas. On the subject of plants for the pond, there are some very invasive species which ought to be avoided at all costs. The worst of these are Australian swamp stonecrop (also known as New Zealand pygmyweed) Crassula helmsii, fairy or water fern Azolla filiculoides, floating pennywort Hydrocotyle ranunculoides and parrot’s feather Myriophyllum aquaticum. All of these are still on sale at some garden centres, although they are causing havoc in some parts of the countryside. Their regenerative powers are astonishing and they can quickly choke ponds and water courses, smothering out all other plants and leaving no open water for insects.
Birds
Many birds will have young in the nest by now so it’s worth looking out for adults taking food to the chicks. Virtually all young birds need insect protein and blue tits and great tits will be constantly searching for caterpillars, since their breeding is timed to coincide with an abundance of this food. The less far the birds have to travel for supplies, the more chance they have of successfully raising their brood, which in the case of blue tits may number as many as a staggering 15, although it’s very rare for more than a tiny proportion of these to survive even into adulthood. You can help their chances by having garden trees which are likely to be rich in caterpillars at this time of year. These include species of willow, flowering currants and apple trees – all very attractive in their own right.
Insects
Most ladybirds will have emerged from hibernation by now although one species – the 14-spot – may not do so until May. Ladybirds (as adults and larvae, both) are well known as predators of aphids but about a third of the 40 or so species found in Britain are vegetarian. Some eat grasses but others feed on fungal diseases on leaves such as rust and smut. All in all, therefore, these little beetles are excellent creatures to have around. Like many other beneficial insects, they benefit from a less than tidy garden since they often overwinter in deep leaf litter.
Bees are far more in evidence now, foraging for food on spring plants like celandine, coltsfoot cowslip, primrose and dandelion. It cannot be an accident that all these species have yellow flowers: bees are presumably particularly attracted to this colour at this time of the year.
Although social bees like bumblebees and the introduced honey bee tend to be better known, most bee species in Britain – an amazing 250 or so – are solitary and quite a large number are found in gardens. The natural nest sites of many of them are holes – whether in hollow plant stems, old bricks or dead wood. If your garden lacks many suitable sites you can provide artificial ones, at little or no cost and with a good chance of success. Paper straws placed in tin cans, or short lengths of bamboo tied together and suspended or packed into a container may often be used by these bees. Alternatively, drill some holes – using different-sized bits to produce as great a variety as possible - into timber. Wherever they are, the cavities should slope down to avoid the danger of their filling up with rainwater. They should also be placed in a sunny site.
Holes like these may be used by other insects besides bees of course – you never know what to expect! Solitary wasps (harmless to humans) may move in. Like bees, these are also beneficial to gardeners but for very different reasons, acting as natural pest controllers and keeping down numbers of aphids.
Slugs
You have to go a long way to find a gardener who has any time at all for slugs – and yet, there is case to be made for them! Slugs are one of the major re-cycling agents in gardens, breaking down dead and decaying vegetation and speeding its almost magical transformation back into the soil from which it came. This is one good reason for not being obsessively tidy since if slugs can’t find this food they will move in quickly on the tender young growth of seedlings. Slugs also provide food for many of the creatures that most gardeners enjoy seeing – song thrushes, common frogs and hedgehogs are examples. Harvestmen - those very long-legged spider look-alikes but with six legs rather than eight like spiders – also eat slugs, as well as a range of other common creatures like centipedes, woodlice and snails.
If you still need convincing that it makes more sense to come to terms with slugs than to wage war on them, what about the fact that it’s estimated that every square metre of your garden supports at least 200 of the creatures? This – and the fact that slug trails towards tender plants will be followed by other slugs – almost certainly means that killing slugs is a fairly pointless activity at best, since an almost endless supply of live slugs is always at hand to fill the ecological gap left by the dead ones.
This doesn’t mean, however, that you have to stand by and watch your favourite plants devoured, as some non-lethal deterrents such as copper tape (which needs to be at least 4 cm wide) and copper mats are quite effective. Removing slugs by hand is not perhaps a task that everyone can stomach but it does work. Displaced slugs can be put to good use on your compost heap.