Many ‘annuals’ we grow have varying degrees of hardiness, and all are relative to our own climate here in Britain – often only named ‘annuals’ because we can’t usually grow them on for longer than a year.
Of course, in other countries, many grow well and cope with warmer conditions, growing on as perennials before returning the next year and some years after that.
In our country these plants are classed as tender or sometimes half-hardy annuals, giving up the ghost when the cold, wet and frosts set in.
It’s always best to get a head start on plants like these, sowing them and growing them on indoors before planting them out in a few weeks. You’re more likely to get a higher success rate like this and gain more control of growth, as opposed to sowing straight in the ground.
Only plant out when there’s no longer any risk of frost in your area, which may be at the end of May, or even slightly later in June. Nights mustn’t get lower than 10C (50F), or your plants may not survive.
Here is a selection of some of the best and most beautiful tender annuals to get going now, for a splendid array of flower colour in summer.
1) Cleome spinosa – Sow thinly and cover with a fine later of seed compost. Keep between 15 and 20C. Harden off and plant out for flowers till October.
2) Ipomoea lobata – Spanish flag climbers have beautiful flame-like flowers for rambling over trellises and obelisks. Soak overnight sow 6mm deep into seed compost at 21 – 24C.
3) Amaranthus caudatus – Sow in pots or trays of moist seed compost and cover with a fine layer of Vermiculite. Keep at a constant of between 20 – 25C. Don’t waterlog compost.
4) Zinnias – Sow on damp seed compost and cover with a layer of Vermiculite. Keep at 20C at least and plant out when plants are easy enough to handle.