Regal and Zonal Pelargoniums
A Blooming Long Life
For generations, these bedding geraniums, which are really ‘zonal’ pelargoniums, have been among the brightest of summer flowers and the most continuous in display (rivalled only by the scarlet salvias), but they are not the only important garden race of pelargoniums Others are the ivy-leaved varieties which are sprawling in habit, the ‘regal’ pelargoniums, mainly valued as pot plants for greenhouse and conservatory, and the scented-leaved pelargoniums, grown more for the many shapes and scents of their leaves than for their flowers which are often rather dowdy.
Zonal pelargoniums flower non-stop from the moment they can be safely planted outdoors in late May or early June until they have to be returned to the safety of a frost-proof greenhouse or other well-lightedsome time in October. Given a minimum temperature of about 13°C (55°F), many will continue to flower much of the winter and spring as well, and all zonal pelargoniums make excellent pot plants in sunny spots.
They are bushy plants with stems that become increasingly woody with age. The name ‘zonal’ refers to a zone or ring of dark colour on the leaves, but not all varieties have this, some being green all over and some variegated, with several colours including cream, yellow and red. Flower colours range from white and pale pink to cherry red, scarlet and crimson and there are double-flowered as well as single-flowered varieties. With the exception of the variegated-leaved varieties, which must be increased from stem , all can be grown from seed or cuttings: the seed should be sown in a warm greenhouse between January and March, the cuttings rooted in a propagator or frame in spring or late summer.
Seedlings are sometimes a little slow coming into flower the first summer, although the F1 hybrids such as ‘Sprinter’ and ‘Carefree’ are much better than the old non-hybrid varieties in this respect. All like warm, sunny places, do not require very richand must be given complete protection from frost.
Ivy-leaved pelargoniums, though natural sprawlers, can be readily trained asto wires or a trellis. Alternatively, they can be grown in hanging baskets, window boxes and other containers. The leaves are smooth and angular in contrast to the more rounded, softly downy leaves of the zonals. The colour range is also more restricted, mainly white, pink, lilac and scarlet, but flowers are produced almost continuously and the plants are equally sun-loving. Increase is by cuttings.
Scented leaved pelargoniums
Scented-leaved pelargoniums have small, not very showy flowers and are grown as foliage plants. They are bushy, like the zonals and regals, but the leaves are of many different shapes. The scents, too, vary as much as the leaf shapes and include lemon, rose and peppermint. They are grown as pot plants in much the same way as the regals.
All pelargoniums flower most freely and continuously if the faded flowers are removed regularly. The regal varieties can be pruned in August to prevent them getting too large or straggly, and the scented-leaved varieties can be similarly pruned at any time in summer. Zonal and ivy-leaved pelargoniums are usually cut back quite a lot when they are lifted in autumn and returned to pots or other containers so that they can be overwintered in a protected place. Most will survive, provided they do not freeze, but the further the temperature falls below 13°C (55°F) the more likely are they to suffer from decay caused by the grey mould fungus, Botrytis cinerea. Occasional dusting with sulphur or spraying with benomyl will help to prevent this.