Why Night-Scented Stocks Earn Their Place on the Patio

Most of us choose patio plants with our eyes. Night-scented stocks ask you to choose with your nose instead. Sown in containers and tucked beside a bench or a back door, they release a rich, clove-like perfume that arrives after dusk and drifts on the warm air exactly where you are sitting. The flowers themselves are modest — small, pale lilac-mauve and rather untidy by day — but that hardly matters when you are catching their scent over a glass of wine at ten o'clock at night.

They are also one of the easiest ways to turn a paved corner into something wildlife-friendly. Because they open and scent in the evening, they are aimed squarely at moths, which pollinate them in return. Pale petals catch what light there is, so a few pots grouped together become a small landing strip for night-flying insects without any effort on your part.

Choosing and Sowing Your Stocks

The one you want is Matthiola bicornis, sold simply as night-scented stock. It is a hardy annual, growing roughly 30–45cm tall, with thin stems and a loose, airy habit. It is not the same as the big, showy Brompton stocks, which are lovely but flower mostly by day.

The crucial point with night-scented stock is that seedlings resent root disturbance. Sow them where they are to flower — straight into the pot — rather than raising them in modules and transplanting. From late March to mid-June, scatter seed thinly on the surface of moist compost, cover with about 3mm of fine compost or vermiculite, and water gently with a rose. Germination usually takes 10–14 days at around 15–18°C. Thin the seedlings to roughly 15cm apart once they are large enough to handle; crowding produces weak, mildewed plants.

For a long season, sow a small pot every three to four weeks. A late sowing in early August will give you scent well into September, when warm evenings are still worth sitting out for.

Pots, Compost and Planting Up

Stocks have deep, fleshy roots and dislike sitting wet, so give them room. A container of at least 30cm across and 30cm deep suits three or four plants; a half-barrel will take a generous drift. Terracotta or unglazed pots are ideal because they breathe and dry out faster, which this plant prefers.

• Use a peat-free multipurpose compost mixed with about a quarter by volume of horticultural grit for drainage.
• Put a layer of crocks or broken polystyrene in the base and raise the pot on feet so water never stands underneath.
• Mix in a slow-release fertiliser at planting time; stocks in containers run out of nutrients quickly.
• Group pots in threes at different heights — an upturned pot as a plinth works well — to create a denser block of scent.

If you are growing a taller strain, push a few twiggy hazel or birch stems into the compost early. The stems are brittle and will flop in wind or heavy rain without discreet support.

Siting Pots So the Fragrance Reaches You

Fragrance travels on still, warm air, so placement matters as much as the plants. Put your pots upwind of your seating and as close to it as you can reasonably manage — a metre away is far better than five. Raising the flowers to roughly seated nose height makes an enormous difference; a low pot at ankle level wastes most of the scent.

A south- or west-facing corner against a wall or fence is the best spot. The masonry holds the day's heat and releases it through the evening, which encourages the flowers to open and the perfume to carry. Shelter from strong wind helps too, both to protect the brittle stems and to stop the scent being whipped away. And do keep a few pots near a frequently used door, so the fragrance meets you every time you step outside.

Keeping Them Going Through Summer

Container stocks are thirsty in dry spells. Water thoroughly in the morning, aiming at the compost rather than the foliage, and check by weight — a light pot needs watering, a heavy one does not. Feed with a dilute high-potash liquid feed once a week from the moment the first buds appear.

Deadhead regularly to keep flowers coming, but leave a few stems to set seed at the end of the season: night-scented stock self-seeds obligingly, and you may find seedlings appearing in neighbouring pots the following spring. Watch for aphids and grey mould in humid weather; a crowded, overwatered pot is the usual cause, and thinning the stems to improve airflow solves most of it.

One quirk worth knowing: the flowers close in dull, cold or wet weather and may not open at all on a chilly evening. On a warm, humid night after a light shower, the scent is at its most intense.

Building a Wildlife-Friendly Evening Garden

Once you have stocks working for you, it is easy to extend the idea. Pale, night-scented flowers are the backbone of any garden designed for moths and the bats that hunt them.

• Nicotiana (tobacco plant) — tall, white and powerfully scented after dark.
• Evening primrose — bright yellow, opening in seconds at dusk.
• Night phlox — low-growing with a honeyed evening perfume.
• Sweet rocket — a cottage-garden favourite that scents the whole garden at twilight.
• Honeysuckle and jasmine — climbers that add height and scent around a doorway.

Keep the area as dark as you can. Security lights and decorative uplighters disrupt moths badly, so leave one corner unlit. Skip insecticides entirely, let a few seed heads stand over winter for birds, and put a shallow dish of water among the pots. Do those small things and your patio stops being somewhere you simply sit — it becomes somewhere the night itself comes to visit.