DESCRIPTION: This is a large group of hardy and tender annuals and perennials that may have shrubby, herbaceous, or climbing growth. Senecios are found wild in almost every country, especially in southern Europe; others are found in South Africa, New Zealand, Australia, China, Japan, the United States and Mexico. They vary in size and shape, particularly their foliage, but almost all have yellow or purple flowers, which resemble daisies and grow up to 3 inches across. They grow in thick trusses over the plant. S. elegans is a hardy annual that grows up to 2 feet high and has pinnate (feathery) or deeply lobed foliage. It produces tight heads of purple, crimson, mauve, rose, or white single or double flowers in the summer. The flowers are great for cutting. S. laxifolius is a dwarf shrub that has oblong or obovate, silvery gray leaves and large bunches of brilliant yellow flowers. It is a good plant for a mixed flower border, shrub border, or sunny rock garden. This plant can only be grown in mild climates. S. Petasitis (Velvet Geranium, California Geranium) is a tender kind that has fuzzy, grayish-green leaves and yellow flowers. It grows well in mild climates. S. scaposus is a tender succulent. It may be grown outside in mild climates. It is a low growing, shrubby plant that has rosettes of plump, rounded linear foliage. The young leaves are clothed with silvery fuzz. As they grow, they produce side branches. Three to five flowers grow atop long stalks. They resemble daisies and each has about 12 ray florets. S. macroglossus (Cape Ivy) has evergreen leaves that resemble those of the Ivy and lemon yellow flowers. S. mikanioides (German Ivy) has similar foliage, but produces clusters of small, rayless flowers. Both have climbing stems that are trained to a trellis or wires. They can be grown in a greenhouse or window of a cool room. S. Cineraria is a popular plant that has large, silvery, lance-shaped leaves that are divided deeply and terminal clusters of cream or yellow flowers. Its variety Diamond has even whiter foliage. S. leucostachys has whiter and more finely divided foliage than S. Cineraria and its variety Diamond. These plants are mainly grown for the beauty of their foliage and are grown as perennials in mild climates.
POTTING: Senecios will thrive in a sunny position and regular, well cultivated garden soil. The herbaceous kinds are great for growing near the water. They are excellent for cultivating on moisture-holding soil, but not for dry, sandy or gravelly soil. Planting should be done in the autumn or early spring. They'll benefit from well-decayed manure being applied every spring. S. scaposus, the succulent kind, should be grown in very porous soil that contains crushed limestone. It should have full exposure to sun and moderate water from spring through autumn; even less in the winter. When the climbing kinds are grown in a greenhouse, they should be planted in pots or tubs of loam and leaf mold. They should be provided with shade from harsh sun. Water should be given abundantly throughout the summer, but only when the soil is fairly dry in the winter. S. Cineraria, its variety Diamond and S. leucostachys are good for cultivating indoors. They should be planted in pots that are just large enough to hold the root balls without crowding. The soil should be porous and sandy. After potting, water the plants well and place in a shady greenhouse or cold frame. When they become established, which may take 3 or 4 weeks, ventilate the greenhouse or frame a bit and keep the atmosphere humid. Sprits the foliage a bit on sunny days and when the plants start to grow again, they may be exposed gradually to sun and ventilation. They will flourish in a minimum winter temperature of 40 to 50 degrees.
PROPAGATION: Seeds may be started inside 8 to 12 weeks before frost-free weather. Set them on the surface and don't cover; they need light to sprout. Maintain a 75-degree temperature until the seedlings show, then grow in cooler temperatures (40 to 60 degrees). Seeds may also be planted outdoors as soon as the weather is frost-free in drills. The new plants should be set a foot apart. The hardy herbaceous kinds may be propagated by seed or by division. Cuttings of well-ripened shoots may be inserted into a bed of peat moss and sand in the fall. Keep them in a cold frame until they have formed plenty of roots, after which they are planted outside. The climbing varieties are propagated by cuttings that are taken in the spring. Tips of shoots, 2 inches in length, may be inserted in small pots filled with sandy soil. Moisten the soil and cover with a bell jar until roots grow. They are then moved to 3-inch pots and as they grow are moved to larger pots and so on. S. laxifolius needs to be increased by cuttings also.
VARIETIES: S. elegans; S. Clivorum; S. Veitchianus; S. Wilsonianus; S. aureus; S. adonidifolius; S. Doria; S. Doronicum; S. laxifolius; S. Petasitis; S. grandifolius; S. scaposus; S. glastifolius; S. multibracteatus; S. macroglossus (Cape Ivy); S. mikanioides (German Ivy); S. tropaeolifolius; S. Cineraria & variety Diamond; S. leucostachys.