Larger than peas, the seeds of nasturtium (Tropaeolum majus) are easy to pick up and sow. We usually start this frost-sensitive annual in small pots indoors in mid-May and set plants out during the first week of June. Nasturtiums—the name means “nose-twisters”—love hot sun and poor soil; in rich, moist ground they go mostly to leaf. Dwarf varieties are best for edging and most sites (other than window boxes, where trailers are required). T. Whirlybird Series includes flowers in separate shades of orange, cream, mahogany, tangerine, peach and rose, but you won't get a better display for $2.50 than with a packet of mixed colours. ‘Strawberries and Cream' is pale yellow splashed with red; ‘Strawberry Ice' is deep yellow and red. (Be warned that any nasturtium listed as tall, climbing or cascading will sprawl over the ground in all directions.) For a display of dark, round leaves and velvety crimson flowers spilling over window or balcony boxes, poke in a few seeds of T. ‘Empress of India'.
Dwarf morning glories
Dwarf morning glories (Convolvulus tricolor) are perfect for large, decorative containers, where they can be seen and appreciated. Last summer, in a garden full of flowers, a single pot of ‘Blue Ensign' dwarf morning glories, sitting on our step, drew more than its share of attention: the startling contrast of navy blue against white flaring out from yellow centres, the trumpet blooms as big as climbing morning glories looking up from bushy plants a mere 35 centimetres tall. Easy to grow from seed pushed directly into the soil of containers around the frost-free date, or started a little earlier indoors, this sun-loving annual starts blooming in mid-July and carries on until stopped by frost in early October. ‘Ensign Mixed' offers burgundy, light pink and pale blue flowers along with the navy; the leaves of ‘Dwarf Picotee Mixed' are mottled green and white, with pink, red or blue flowers edged in white.