During the heated days of late summer, few but the most enthusiastic of gardeners care to loiter in the open garden until evening. Then, the sun having sunk in the west, we venture forth from the shade of house or of trees, and leisurely walk the round of our paths, refreshingly fanned by the little rippling breeze which makes the leaves flutter as it rhythmically comes and passes. The last bees have reached their hives, laden with the sweet product of their hard labour. The honeyed flowers, which look to their visits and to the visits of other sun-loving insects for aid in fertilisation, have, so far as possible, covered their tempting cups to avoid the damping or loss of the precious pollen within. Snails and slugs crawl from hidden caves, prepared to work in darkness the evil which fear of feathered warders hinders by day. Except for these workers of ill, these foes of beauty, the garden is apparently going to sleep. But wait. Wherefore is this increasing fragrance streaming from the honeysuckle trellis into the cooling air—a fragrance surely not without seductive purpose? Straight as the course of a homeward bound bee, a hawk-moth flies to the expanded blossoms and extracts the honey from the narrow tubes, too deep for bee or wasp to sound. Look, too, at this bed which but an hour ago showed nothing but a green mass of leaves serrated as those of dandelions. Great white flowers, three inches or more across, have now appeared and produce a truly wonderful effect. These are the flowers of one of the evening primroses (Oenothera taraxicifolia), originally imported from America. Not so pure a white are the larger blossoms of another evening primrose (Oe. marginata) which is just beginning to send forth from the border a fragrance as of magnolias. The old double white Rocket (Hesperis matronalis), or Damask Violet, as it was formerly called, smells more strongly as evening draws in, and its scent now takes on the character of the scent of Violets. Even more noticeable is the delicious fragrance which begins to be yielded by the Night-scented Stock (Hesperis tristis), a fragrance which will continue until the commencement of the dawn. In the presence of these happenings, we begin to realise that the garden is not after all asleep. Indeed, we see that a part at least of the living beauty of nature only awakes at the approach of night.

Convention rules over us, and in the most unlikely places we see those unadaptive, stereotyped results which mark the realms where she is sovereign. How otherwise can we account for the fact that, although evening is the best time for enjoying the flowers of our gardens during the months of July and August, few gardeners ever think of devoting any part of their borders to the cultivation of flowers which bloom at night? Yet the pleasure to be obtained from them is very great, and the possible variety is considerable. Nearly all are fragrant, as otherwise it would be difficult in the darkness for them to attract the moths which they mostly desire as pollen bearers.

None of these flowers of night are more remarkable than Silene nutans, one of our native catchflies (so called from their viscid stems which prevent ants and creeping things from reaching and robbing the honey stores), which may occasionally be seen growing on limestone rocks. This plant bears many large white flowers during June and July, each flower living but for three nights. At about seven o'clock of the first evening, the flower quickly opens and emits a strong scent as of hyacinths. Five of its stamens quickly develop, the pollen ripens and the anthers burst. At three o'clock in the morning, or thereabouts, the scent ceases to be produced, the five anthers wither, and the corolla closes. During the following day the flower looks as though dead or dying. At the same hour as on the previous evening, however, it again opens and again becomes fragrant. Five more stamens develop and ripen their pollen, after which the plant again closes as before. The proceeding is again repeated on the third night, the pistil, however, now developing instead of the stamens. The stigma having been fertilised with pollen brought by moths from another flower, the corolla closes as before in the early morning, and never again reopens. Other of the Silenes, such as S. noctiflora, S. inflata, S. vespertina, and S. longiflora, also bloom at night and are equally interesting.

Almost a shrub in size, the Marvel of Peru (Mirabilis jalapa) is one of the handsomest of night blooming plants, opening its variously coloured ephemeral flowers at about eight o'clock, and closing them again for good and all before three o'clock the following morning. It is a somewhat delicate plant and will only thrive in warm soils and sunny situations. A plant not often seen in gardens is the fragrant Sand Verbena (Abronia fragrans), a Californian perennial of fairly vigorous trailing habit, producing a quantity of beautiful flowers of purest white which open and yield a vanilla-like fragrance at night.

Although too delicate to be grown all the year through in the open air of this country, several of the Thorn apples or Daturas can easily be grown as half-hardy annuals, and during July and August are objects of great beauty. The mauve-tinged white trumpets of D. Ceratocaula which open and afford sweet fragrance[65][66] at night are especially handsome, but some of the other kinds are almost equally worth growing.

In addition to the evening primroses already referred to, there are several other very attractive species, some being delightfully fragrant. They are quite easily grown in almost any soil, and night-gardeners should cultivate all of them. Oenothera eximia, which likes a light soil, is one of the best of the white-flowered kinds, its scent somewhat resembling that of the magnolia. Oe. speciosa (white to rose), Oe. odorata (yellow), Oe. fruticosa (yellow), Oe. macrocarpa (yellow), Oe. biennis grandiflora (yellow), and Oe. triloba (yellow) are but a few names. Some of the evening primroses remain more or less open in the daytime, in which case they are usually visited by bees as well as by their guests of the night.

The catchflies are a family of night-bloomers, and their relative, the Soapwort (Saponaria officinalis), resembles them in this respect, for its large rosy flowers open and become fragrant much after the manner of those of Silene nutans. The common pinks, too, which are allied plants, yield increased fragrance during the hours between sunset and sunrise, and are then frequently visited by moths.

The petunias are not often capable of being grown as hardy perennials in English gardens, but are easily grown as half-hardy annuals. They lend much beauty and fragrance to the night-garden, the white P. nyctanigiflora being especially good. All the scented pelargoniums are delightful, the night-scented P. triste and P. atrum being as good as any. The hardy terrestrial orchids, Habenaria bifolia and H. chlorantha, which yield their spicy fragrance at night, are easily grown in the bog garden, or indeed in any damp shady place if plenty of leaf-mould be mixed with the soil.

Although usually to be seen only under glass, it would be impossible to dismiss the subject of night blooming plants without referring to the ephemeral blossoms of the night-flowering cactuses, Cereus grandiflora—with its vanilla scented brown and yellow flowers, often measuring a foot across—and C. nycticalus, known as the Queen of the Night. The flowers of these plants open at about nine o'clock and begin to wither some six hours later.

One might go on adding to the list, but, even from the few plants here enumerated, it will be seen that the night gardener has a considerable field in which to work; whilst to those who share Baudelaire's love of scents, the realm of night-blooming flowers should be a very Paradise.