Somewhat closed-over during daytime, but opening fully in the creeping twilight of sundown, evening primrose flowers have an ethereal quality.

The large flowers remain remarkably bright, even as darkness sets in. It is almost a glowing effect and it is very summery and can transform a garden with a magical touch on a quiet calm summer evening.

It is easy to understand how this flower got its common name – its flowers are a light soft yellow and they open in the evening. However, evening primrose only shares its pale yellow flower colour with primroses and is not related. Instead, it is related to the willowherb family, and the link can be seen in the wiry flower stems and pointed flower buds.

Its flowers open in the evening for pollination by night-flying months, which come to get some nectar from the flowers, and incidentally carry pollen to the next flowers. It also emits a lovely fragrance on a warm, calm night.

Each flower lasts just a few days, but they are carried in succession over a long period through summer and autumn.

The wiry flower stems generally do not need staking and stand up very well, perhaps leaning over in a windy garden. The height of the flowering stems varies between 60cm in dry poor soil to over 150cm in rich ground.

The common evening primrose is an annual or biennial, late-sown plants flowering the following year.

This plant is the source of evening primrose oil, used medicinally for relieving stress. The oil is pressed from the seeds. The plants, once they have been planted out, tend to self-sow around the place for years, but never become a weedy nuisance.

Even if no plant appears for a few years, seedlings can pop up years later after a little soil disturbance. And plants can appear in gardens unexpectedly, but obviously carried in the pot of another plant or on footwear or soil.

The common evening primrose, Oenothera biennis, is native to North America, although it is naturalised in many parts of the world. It is not unusual to see plants or groups of plants in rural gardens, but for some reason, not so much in town gardens.

This is probably because the evening primrose has a wildness, a natural appearance, that suits a rural setting but can look untidy in a town garden.

This flower is pretty on its own but looks well with blue agapanthus, drooping purple dierama, white daisies and tall red crocosmia, and that is even by day when the flowers are half-closed.

There is a perennial variety, Oenothera fruticosa, with smaller flowers and deeper yellow colour, although there are lemon-yellow versions. It makes a medium-sized plant that flowers over a long period and will last for years, unless the soil is heavy and wet in winter.

The lovely low-growing Oenothera missouriensis is perfect for the front of a bed or border, or a large rock garden. This one has bright lemon-yellow flowers, 8cm across, and is very eye-catching. It is a vigorous plant, growing from a central rootstock with reddish stems trailing along the ground and carrying the large flowers.

The white evening primrose, Oenothera speciosa, is a lovely plant, reaching about knee-height, with white cupped flowers. A pink form called ‘Rosea’ is the one usually seen for sale. Both of these are mountain natives and, though they look delicate, they are completely hardy. Given a dry soil, they are fine, but too much dampness will cause root rotting problems.

All kinds of oenothera can be raised from seeds, sown in spring or mid-summer. CL

Fireblight hangs on

Fireblight is not mentioned much these days since other severe plant diseases, such as ash dieback, oak wilt and chestnut blight, appeared. It was once considered to be a threat to hawthorn hedges, apple trees, pears and many other related plants, but that did not happen. However, there is lots of fireblight about still, affecting garden shrubs, notably pyracantha and cotoneaster.

It is called fireblight for the way the leaves on twigs turn brown and dry just as if a bonfire had been set too close by. But there are other symptoms too. Affected twigs of current-year’s growth hang over at the tip in a crozier shape. Affected branches exude droplets of white or creamy liquid, which contains bacteria to spread the disease to new sites. If you have a pyracantha or cotoneaster showing these symptoms, it should be dug out and burned.

Flowers

Cut back perennials that have gone over because many of the early kinds will give late flowers if cut right back, and it tidies messy foliage out of the way. Container plants of all kinds will need frequent watering, perhaps every day if the weather is hot and dry. Most need warm weather to perform to their best. Feeding is essential.

Lawns

Lawns are looking well, having had good growing conditions all summer. Feeding can be applied now if a lawn is pale or yellowish. Lawns need to be fed at least twice each year, most need the second one now. There is now a good chance to control lawn weeds with a lawn weedkiller or grassland weedkiller.

Trees, shrubs and roses

It is time to clip hedges of all kinds before the wood gets tough. Any heavy cutting back should be left until the start of the growing season next year. Roses should be sprayed against blackspot disease and the similar leaf spot disease. Make sure that moisture levels are adequate to keep young trees growing.

Greenhouse and house Plants

Continue watering and feeding greenhouse plants and house plants. Take cuttings of all kinds of shrubs now, especially deciduous kinds. It is too late to spray a grapevine if it shows mildew. Be especially careful to water plants in pots or grow-bags regularly, as these can easily dry out. Train and side-shoot tomatoes and cucumbers.

Fruit, vegetables and herbs

Remove vegetables that have gone over because of the warm weather. Make some late sowings of lettuce and radishes. If the soil is dry, peas and cabbages should be watered to keep the plants growing. Harvest and use, or freeze, vegetables and herbs in good time as they become ready. Apply blight sprays if there are warnings..