Too many people think of climbers as permanent residents in the garden, yet many excellent types can be grown from seed. Perhaps the most familiar is the climbing form of nasturtium, often used to cover walls during the summer. Nasturtiums are easier than almost any other plants to raise from seed, and the only mistake you can make is to treat them too well. They thrive in poor, undernourished soil, though they relish sunshine. Climbing nasturtiums are usually sold as seed mixtures containing a range of yellow, red and orange-flowered forms.
Anybody who has tried to eradicate bindweed will wince at the prospect of deliberately planting one of its relatives, although the ornamental convolvulus is a much more amenable plant that will rapidly cover a trellis. Like the nasturtium, the convolvulus prefers poor soil and is most often sold as a mixture containing white, cream, blue and rose-pink shades.
For a sunny position, try a relative of the convolvulus, the half-hardy morning glory or ipomoea. The most reliable blue form is ‘Heavenly Blue’, although red and white-flowered types are available. The seed may need nicking to aid germination.
For really quick cover, use Humulus japonicus variegatus, the ornamental hop. The more familiar golden hop. H. lupulus ‘Aureus’ cannot be raised from seed.
Sweet peas are excellent as informal climbers. Give them a start with twigs, and let them romp away. Probably the most suitable for decorative form are the ever-blooming forms like the mixture ‘Galaxy’. Alternatively, consider the runner bean. After all. Choose a mixture of red and white-flowered varieties and you will have not only a most attractive climbing plant, but one that will feed you too.
The orange-flowered Thunbergia alata, or black-eyed susan is also easily grown from seed and climbs to about 6ft.