With flowers looking almost exactly like the common daisy of lawns, it is clear that the Mexican daisy is a relative. The flowers are the same size as the lawn daisy, less than 2cm across. They are composed of a ring of ray florets, specially formed to attract pollinating insects and have a yellow centre formed of a clump of tiny true flowers. These are the part of the flower that produces seeds.

The flowers are produced in profusion over a period of many months. They open from pink buds, pure white and later they take on a pink hue, darkening as they age to a deep wine colour, giving a great background for the fresh white flowers that constantly open.

The flowers are produced from late spring to autumn. Very few garden flowers have such a long flowering time, the peak occurring in mid- to late summer.

After the flower has faded, small tufted silky seedheads are produced, which soon shed and never look untidy.

The Mexican daisy, sometimes called Mexican fleabane, Erigeron karvinskianus, really is from Mexico and indeed much of the rest of Central America, but it is completely at home here and in many other parts of the globe that it has managed to reach. For a Central American plant, it is remarkably hardy and can survive in any part of Ireland, though it is mostly seen in coastal areas. Being so hardy, it is likely that it occurs at altitude in its native range. Although it was introduced as a garden plant, it has found its way outside the garden and appears as a naturalised plant in many places, typically with exceptionally good drainage, such as old walls, stone bridges, excavated rocky banks and roadsides.

It likes perfect drainage, being able to root down deep into rock fissures or old mortar or the cracked concrete joints of walls and stone bridges.

Its seedheads release the seeds equipped with feathery silk that allows them to be blown to new sites. They tend not to blow very far, usually dropping to the ground close by the parent plant. New seedlings spring up with great ease and soon a colony of plants is formed.

The plant is perennial, with a tough wiry root from which the flowering stems arise. The stems can be dense covering the plant’s bit of ground and preventing weed competition.

Sometimes, in a nursery or a garden centre, seeds find their way into pots of other plants and the Mexican daisy can appear in gardens on its own initiative. If it does, take it as a bonus and plant the little plant in a suitably sunny, well-drained spot.

It is good in a large rock garden, but might be too enthusiastic for a smaller rockery. It loves steps, walls, banks and the like.

If you can get hold of a plant, this is a good time to plant because it gives it a chance to get some rooting done before the drier months. It can only thrive in such dry places because it roots deeply.

If you cannot find a plant, it can also be grown from seeds. Anybody who has the plant will also have plenty of seeds to give away.

A single seedhead is enough to establish, quite quickly, a significant colony. If that is not possible, some of the seed companies offer seeds for sale. It can be in flower in little over three months from seed and having once sown it, it will be with you, self-sown, ever more, but never a weed. CL

Mizuna greens

Mizuna, or Japanese mustard, has been grown in Japan for centuries and used as a salad green and for stir-fry cooking. It is a form of mustard, a member of the cabbage family.

Like the other leaf mustards, it has a peppery mustard taste, but is much milder than some of the other larger mustards, and not as peppery as rocket. It can be mixed with lettuce or other greens to spice them up a little.

It is a great winter green vegetable, withstanding cold weather very well. It can be sown in spring and usually soon bolts but the flower heads can be used too and it needs to be repeat-sown.

Sown in late summer or early autumn, it grows well in cooler, more moist weather. The photograph shows mizuna in January.

This week

Flowers

If the soil is not too sticky, over-grown herbaceous flowers can be lifted and divided as they will soon start to grow. Shabby flower stems can be tidied away or they can be chopped up and left on the soil surface as mulch. Begonias and dahlias can be started off from now on in a greenhouse or on a windowsill indoors.

Trees, shrubs & roses

This is a good time to plant trees, shrubs and roses if the ground is not too wet. But wait until the ground is well-drained because young trees and shrubs can suffer badly and not take by being planted into wet soil. Bush roses and repeat-flowering climbers should be pruned in the next two weeks, if not already done.

Fruit, veg & herbs

Early potatoes benefit from being sprouted before planting. If not too wet, ground for vegetables should be cleared of weeds and dug over in preparation for sowing as soon as possible. Do not use a rotovator if the ground is not ready. Fruit trees and bushes can be planted now and there is a wide range available.

Lawn

If the ground is not soggy, lawn areas should be mown as early as possible. Grass grows a little over winter and there can be a lot of grass to mow if it is left until March. If there is heavy moss growth, a lawn mosskiller can be applied at this stage, with feeding later in spring to boost competitive grass growth.

Greenhouse & house plants

Greenhouse peach trees should have the first flowers gently pollinated with a small soft paintbrush or by vigorously tapping on the support wires. Water a peach tree or grape vine well to encourage early growth and allow to drain. Begin feeding plants that are showing growth.