Hartley Magazine

All the latest news, hints, tips and advice from our experts

Sowing biennials – sweet rocket and night-scented stock

The greenhouse is full to bursting at the moment with tomatoes coming into fruit, peppers still thinking about making fruits but looking very happy and healthy as they do, as well as a couple of cucumbers, a melon and lots of basil plants, created from buying one supermarket pot and splitting it, to make a whole jungle of basil. But I have had to make a little bit of space among all the greenery, because it is time to start looking ahead to next summer.

This is a moment in the year when a greenhouse has a couple of different functions. Arguably the tomato extravaganza is its primary one. It is most probably why I have the greenhouse, in all honesty – a place that is reliably warmer and more sheltered than any other corner of the garden, where I can bring on the vegetables that I love most of all, but that don’t entirely love our variable climate. There is one way to get big, juicy, savoury beefsteak tomatoes, fully ripe and still warmed by the sun, and this is it. So, the greenhouse is very much fulfilling its purpose, but it is also a place for preparation for future seasons, and that work can’t stop now.

It is now time to sow biennials in the greenhouse for next summer’s flowers.

It is time to put it to use for seed sowing again. Obviously, there was a lot of this in the spring at the main seed sowing time, but most of these seedlings have moved out to the vegetable beds now. It is time now to sow biennials, for next summer. Biennials grow one year and flower the next, and they are a really good way of getting flowers early in the year – unlike annuals they will have already done the bulk of their growing before the spring begins, and so all they have to do is concentrate of flowering. It just so happens that two of the most beautifully scented of flowers are biennials, and need to be sown now. Sweet rocket, Hesperis matronalis, has white, lilac to deep purple coloured flowers that look a little like those of honesty, while night-scented stock, Matthiola bicornis, produces clouds of small, lilac, four-petalled flowers. Both are sweetly and strongly scented, both at their strongest in the evenings.

I sowed mine a week or so ago, and they can be sown throughout July. Sow into a seed try or plugs and when they have germinated, prick them out into separate pots. Tip the whole compost block out of the pot onto a bench or table and very gently separate out the seedlings, holding them by the leaves and not by the stem, which is very delicate and easily damaged. Fill a small pot with fresh compost and push a dent in the centre, then drop in a single seedling and backfill with compost, pressing down gently. Water and place back in the greenhouse or – if the weather is very hot – in a sheltered spot in the garden, ideally on a table or bench or otherwise away from slugs. Woth regular watering these plants will put on loads of growth within a few weeks, as the weather is so warm and conducive to growth now. You can then plant them into their final positions in early autumn or keep them in the greenhouse over winter and plant them out in spring.

I’ll probably pop mine out as soon as they look big enough and hope for the best over winter, just to save space indoors and leave it clear for next spring’s sowings. A great place to plant them out is near a terrace or a patio that you use a lot during summer evenings, as you will then have wafts of beautiful scent accompanying your evening G&Ts next summer.