Pelargonium
Pot Cultivation
The best compost to use for Zonal pelargoniums consists of two parts of fibrous loam, one part of leaf mold or peat moss, a little lime, and a generous addition of sand. After potting, no water should be given until the soil is almost dry, then it should be thoroughly saturated. Continue with this method of watering until they have grown a sufficient amount of roots, and throughout the summer, weekly applications of fertilizer or liquid manure should be given. Too much shade and nitrogen in the soil will encourage lush growth and few flowers. Towards the end of summer, the water supply should gradually be reduced. During the winter, except in areas with mild climates, they must be kept in a room or greenhouse with temperatures between 40 and 50 degrees. From October to March, just enough water is given to prevent the leaves from withering. To force these plants to bloom throughout the winter months, cuttings can be inserted from March to May, and when well rooted, they should be potted in 3-inch pots and, later, in 5- to 7-inch pots. The tip of the main shoot and the side branches should be pinched out. They are then allowed to grow unchecked, except that all the flower buds should be removed until the end of September. From June to September, they should be set outside and buried to their rims in a bed of ashes or sand in a sunny spot so their shoots will ripen. Keep the soil moist and add a dilute liquid fertilizer once a week. Near the end of September they are placed in a sunny window or greenhouse with a minimum temperature of 50 degrees. Daytime temperatures shouldn't exceed 55-60 degrees. They will produce flowers continuously throughout the winter. In the spring (whether they have been forced to bloom throughout the winter or not) the branches are pruned back to ensure bushy growth.Propagation
Zonal Pelargoniums: Cuttings may be inserted in late summer or in winter; the summer ones (taken in August or September) create the best plants, however. A cut is made below the third or fourth joint, and only two leaves are left at the apex. All flower buds are removed, as all the stipules (small leaflike appendages at the base of the leafstalks). The cuttings are then laid on a bench in a dry atmosphere to allow a corky skin to form over the cuts. This prevents them from rotting. They are then inserted in a bed or pot of firmly packed sand in a greenhouse or under a bell jar in a window. Keep the sand moist but not soaked. Enough ventilation is provided to keep the atmosphere from being too humid and stuffy. When they have formed roots, 2 inches long, they are potted in 3-inch pots. When they are well rooted, they're gradually hardened off and planted outside in May or June. Pinch the tips of the main shoots to encourage bushy growth. Ivy-leaved Geraniums are propagated in the same ways as the above Geraniums.Show Pelargoniums: In July, the stems of the old plants are cut back to three or four buds and they are sprayed occasionally to induce the growth of new side shoots. When they are 2 inches long, they are detached and planted in pots of sandy soil. They're placed in a cold frame in a moist and shady area. When they've formed roots, they are potted in 4-inch pots and placed on a shelf near the glass in a greenhouse with a minimum winter temperature of 45-50 degrees at night. Don't water the soil until it becomes fairly dry, and throughout the winter the same method is continued. In January, the plants are repotted in 5-inch pots. The tips of the main shoots are pinched out and as the pots fill up with healthy roots and the days lengthen, increased amounts of water are given. Weekly applications of dilute liquid fertilizer should be given from March until the flowers open. After flowering, they should be set in a sunny spot. From then until they are pruned, only enough water is given to keep them from completely drying up. They're pruned in July and either repotted in larger pots or the side shoots can be taken off and used as cuttings.
Herbaceous Pelargoniums: These can be increased by division or seeds. Seeds can be sown in well-drained pans of sandy soil, which is moistened and covered, with a pane of glass. It is then set in a cold frame until they sprout. The glass is removed and when they're large enough to handle, they are planted in a seed box, watered, and shaded from sunlight until they're established. After they are hardened off, they're planted 6 inches apart, in a sunny bed and finally transplanted into their permanent positions in the spring.
- Zonals: Numerous varieties in cultivation have originated from crossbreeding between P. zonale and P. inquinans. The most popular for summer bedding, window box and pot cultivation are: Alphonse Ricard, California Beauty, Enchantress Fiat, Fiat Queen, Fiat Supreme, Madonna, Mme. Buchner, Maxine Kovaleski, New Phlox, Olympic Red, Pink Phenomenal, Poinsettia, Radio Red, Red Fiat, and Snowflake.
- Ornamental-leaved Zonals: Leaves variegated with white or cream: Beckwith Pride, Flower of Spring, Hills of Snow, Mary Ann, Mme. Languth, Mme. Salleroi, and Silver Leaf S.A. Nutt. Leaves variegated with yellow: Crystal Palace Gem. Leaves yellow variegated with bronze: Alpha, Bismark, Bronze Beauty, Graves Jubilee, Jubilee, Pink Marechal MacMahon, and Red Marechal MacMahon. Leaves green with a narrow, black-purple band: Distinction. Leaves yellow: Cloth of Gold, Dwarf Gold Leaf, Gold Leaf, Golden MacMahon, and Verona. Tricolors and quadricolors: Achievement (black-purple, red and yellow), Happy Thought (green, yellow and bronze), Miss Burdett Coutts (green, cream, bronze and pink), Mrs. Henry Cox (green, red, purple and cream), Mrs. Pollock (green, red, yellow and orange), Pink Happy Thought (green, yellow and bronze), and Skies of Italy (Green, cream, purple and orange). Dwarf and Miniature Zonals: Black Vesuvius, Carlton Pet, Dopey, Imp, Madame Fournier, Kleiner, Leibling, Milky Way, Pigmy, Pixie, Sirus, and Venus. Birds-egg Geraniums: Baudelaire, Curiosa, J.J. Knight, and Skylark. Rosebud Geraniums: Apple Blossom Rosebud, Crimson Rosebud, Pink Rosebud, Salmon Rosebud, and Scarlet Rosebud.
- Ivy-leaved geraniums: Alliance, Charles Turner, Comtesse de Grey, Diener's Lavender, Galilee, Intensity, Jeanne d'Arc, Mme. Margot, and Sunset.
- Show and regal geraniums: Autumn Glow, Chicago Market, Diener's Giant, Duchess of Kent, Easter Greeting, Empress of Russia, Lavender Queen, Marie Rober, Mrs. Layal, Rhapsody, Royal Velvet, Springtime, and Winter Cheer.
- Scented-leaved geraniums: P. Camphor Rose; P. capitatum; P. citrosum; P. Clorinda; P. crispum; P. crispum variegatum; P. crispum variety minor; P. denticulatum; P. Dr. Livingston; P. Fair Ellen; P. fragrans; P. graveolens; P. graveolens minor; P. Gray Lady Plymouth; P. Lady Plymouth; P. limoneum;+ P. limonium variety Lady Mary; P. odoratissimum; P. Old Scarlet Unique; P. Prince of Orange; Prince Rupert; P. Rober's Lemon Rose; P. quercifolium; P. radens; P. Rollison's Unique; P. scabrum.
- Succulent geraniums: P. echinatum; P. gibbosum; P. glaucifolium; P. tetragonum; P. dasycaule.