Nasturtium

Nasturtiums are about as forgiving as a flower gets, which makes them perfect for a spot you've been neglecting. The single biggest mistake folks make is feeding them too well — rich, nitrogen-heavy soil gives you a jungle of lush leaves and almost no flowers. Plant them in your worst, leanest ground and skip the fertilizer entirely. Direct sow after your last frost date; the seeds are big and pea-like, so push them about half an inch into the soil and they'll come up reliably in a week or two. I prefer direct sowing over transplants because nasturtiums resent root disturbance and sulk for weeks if you move them. They're frost-tender, so don't rush them out too early — wait until the soil has genuinely warmed. Give trailing types something to scramble over or let them spill from a raised bed, and keep an eye out for aphids, which adore the undersides of those round leaves. Oddly enough, that aphid magnetism is sometimes a feature: gardeners plant them as a trap crop to lure pests away from beans and brassicas.

The whole plant is edible and that's the real joy of growing them. Young leaves and the open flowers have a bright, peppery bite — think watercress with a little more punch — and they liven up a plain summer salad like nothing else. The unripe green seed pods can be pickled in vinegar to make a passable substitute for capers, which is a fun project if you have a glut. Medicinally, nasturtium has a long history as a folk remedy; it's rich in vitamin C and was traditionally used as a mild antiseptic and to support the respiratory system during colds, with old herbals praising it for easing congestion. The leaves contain compounds with genuine antibacterial properties, which is likely the kernel of truth behind those traditional uses. Just harvest from plants you haven't sprayed, give everything a good rinse, and enjoy them fresh — the flavor fades fast once picked.