Gardening | native is friend and foe

IDENTIFICATION: While some mistletoe mimics the growing habit of their host, others like the drooping mistletoe, are easier to spot among the foliage. Mistletoe is a parasitic plant which feeds on a host's own nutrients.
IDENTIFICATION: While some mistletoe mimics the growing habit of their host, others like the drooping mistletoe, are easier to spot among the foliage. Mistletoe is a parasitic plant which feeds on a host's own nutrients.

Some trees and larger shrubs in local gardens or on footpaths, particularly in High Street East Maitland, are presently covered in attractive orange and red flowers on weeping stems. In fact, these displays are mistletoe, a potentially harmful parasitic plant.

Mistletoe is one of the more mysterious plants that occurs in the bush and the home garden. Many people would know the clumps of foliage caused by mistletoe on gum trees, although some may not recognise the flowers that the mistletoe plants produce.

There are about 90 species of mistletoe that are endemic to Australia and many of them play an important role in the food chain of native animals and birds.

Possums, gliders and birds all rely on the mistletoe as a food source at different times. In areas where bush has been damaged through fire and the numbers of native animals have been reduced dramatically, mistletoe can become quite extensive.

However, where there are good numbers of native animals, a beneficial balance of mistletoe and animals often results.

Some mistletoes are very host-specific, mimicking the growth of their host plant, producing foliage that is very similar.

The sheoak mistletoe, growing on native casuarinas, produces long pendulous growth with spiny leaves. The drooping mistletoe, which attaches itself to eucalypts, is much easier to recognise, producing growth that is denser in nature and often more yellow/green in colour.

The Australian mistletoe bird (about the size of a robin, with bright red chest feathers) is responsible for spreading many of the plants through the bush, as well as local gardens.

Like many fruit-eating birds, these species have a relatively simple digestive tract, so that the seed passes through the bird rather quickly, leaving the seed with a coating of glucose. The single seeds are contained in a small, sweet, sticky fruit. The sticky layer dries and causes the seed to become attached to the branch. This leads to rapid germination.

When the seeds germinate, a modified root penetrates the bark of the host’s stem and forms a connection through which water and nutrients pass from the host to the mistletoe.  They do this by melding their root structure into the woody structure of the host’s stem, which becomes a living part of the stem receiving all the nutrients that the foliage of the host plant receives.

The growth of the mistletoe often restricts nutrient flow further along the host branch, and the end part may die, leaving the mistletoe in a terminal position on the branch.

Many birds, including the grey goshawk, several species of pigeons and doves, honeyeaters, wattlebirds,  and friarbirds, prefer to nest in mistletoe because it provides shade and cover.

Quite a number of butterfly larvae also feed on mistletoe, and some caterpillars can completely strip mistletoe of its leaves in a matter of months, providing another natural check on the plant.

Mistletoe flowers are usually quite attractive and feature thin “petals” in colours of red, orange or yellow. They also are often pendulous, some hanging to quite some distance from the host plant, while others have a more upright growth.

Apart from appearing on native plants, mistletoe can also occasionally be found on exotic species, tending to prefer plants with more woody stems and trunks, such as roses.

In these instances, they will be more easily recognised as their foliage will be quite dissimilar to the host plant.

The mistletoe should be cut from the stem as its growth will detract from the plant, absorbing nutrients that would otherwise be used in flower production.

Totally herbaceous

In addition to providing flavourings for foods, many herbs that are grown in home gardens can also assist in repelling unwanted pests.

Basil, which is an excellent companion for inclusion in tomato recipes, helps repel flies and mosquitoes. A strawberry patch that has some borage plants included should produce higher yields.

Catnip, because of its particular aroma, will repel fleas, ants and rodents.

Fennel and tansy will also achieve similar results. Tansy leaves, when placed into the compost bin, will assist in the fermentation process.

Cabbage white moths can be deterred from garden beds where cabbages, broccoli, cauliflowers and other similar plants are growing by planting mint, sage or nasturtiums nearby.

Rose plants will benefit from the placement of different herbs in the garden. Garlic and chive plants will help to keep aphids away from the rose plants.

Many vignerons have rose plants at the ends of rows of grapevines.

This helps vignerons identify impending diseases or insect attacks as the roses plants will be affected first, enabling the appropriate treatment to be carried out before the problem becomes serious.

Nitro boost

Members of the legume family (peas, beans, etc.) trap nitrogen from the air in nodules on their roots.

When these crops have finished producing, the plants can be dug into the soil so that the nitrogen is available to the next crop.

Being leafy vegetables, the brassica family (cabbages, broccoli, etc.) require a lot of nitrogen to grow, so it is beneficial to the plants to follow summer pea crops with winter cabbages that can use this free nitrogen source.

Maitland and District Garden Club