Flowering shrubs are a welcome addition to any greenhouse. They have blooms over a long period of time and foliage that is very attractive after the flowers are gone. Even though you specialize in single plants such as camellias, carnations. African violets, orchids or ornamental foliage plants, a few shrubs grown along with your favorites add an extra interesting touch. Contrary to popular belief, there are many beautiful shrubs that are easy to grow. You will see them quite frequently as you visit home greenhouses.
Senecio petasitis is one of my favorites. A native of southern Mexico, this handsome winter-flowering plant, bears big terminal heads of bright, daisy-like flowers. They are bright yellow and stand out bravely in contrast with large velvety soft leaves. This plant takes quite a lot of space, so two are about all I can manage in my small home greenhouse. They are full and tall. The first year they flowered beautifully in 6-inch pots when 2 feet tall, but now they are in 8-pots and reach 4 feet when flowering. But what a mid-winter show! Try this plant if you run your greenhouse cool (50 degrees).
New plants are easily made from cuttings taken from June to August. They reach flowering size the following winter. In August, the young plants are transferred to 4-inch pots. Loose, rich heavy soil suits this plant very. well. After it becomes well established, feed every two weeks with a weak solution of liquid fertilizer. By late fall the plant will be ready for a 6-inch pot.
Naturally Compact Grower
This senecio is a naturally compact grower, so no pinching is necessary. After flowering, you can cut the stems far back, say to 6 or 8 inches, then rest by keeping soil moderately moist until June when the plants can be repotted if necessary. Shake old soil from roots. A transfer to a 9-inch pot might be beneficial but mine have done well in an 8-inch pot.
Another good greenhouse shrub for yellow bloom is genista (Cylisus canariensis) It comes into flower a little later for me than the senecio, making a delightful succession of bright bloom. The flowers are pea-shaped, in terminal clusters and are so profuse they practically hide the foliage. This is another of those evergreen shrubs that can be self-perpetuated year after year from cuttings – a point to remember when selecting flowering pot plants.
Other shrubs you might enjoy include: Boronia heterophylla; Lady-of-the-Night (Brunfelsia americana); ixora; Sparmannia alricana; Mexican-Orange (Choisya ternata); and Polypgala Dalmaisiana. But more about them next month! We must now consider the big possibilities for winter bloom to be had from seed sown this month.
August Planting Notes
Alstroemeria – Sow seed thinly for this tuberous rooted member of the amaryllis family. Its flowers in red, yellow, and purple are attractive and you’ll find it easy to grow. Young plants are inclined to damp-off, so transplant as soon as they are large enough to handle. A temperature of 50-60¡ suits this plant. Shade during the summer.
Brodiaea – If you’ve never tried this semi-hardy plant that has funnel-shaped flowers on long. wiry stems. it will give you something new to enjoy. Corms should be planted now and watered sparingly until growth starts. Grow in poor sandy soil that drains well. A night temperature of 55¡ is satisfactory. Dry off gradually, after flowering.
Calendula – Seed sown by August 10 and benched in September will flower in mid-winter. Grow cool at 40-45¡ at night. Higher temperatures produce soft. weak stems and small flowers.
Carnations – The last pinch should be made August 15. Continue to feed and spray at 2-week intervals.
Freesias – For early blooms start freesia corms this month. They make nice specimens in 6. to 8-inch pans. but for cutting they are easier to handle when planted in seed flats. Another plant you might consider growing along with your freesias is Lapeirousia (Anomatheca), which is handled the same way. It produces red or blue blooms on wiry stems, and while not fragrant or as attractive as freesias. gives you something new and interesting. It produces flowering-size plants from seed within a year.
Cape Cowslip (Lachenalia) – Bulbs should he potted in rich, fibrous loam that drains well. Do not grow at a temperature over 50¡ or flower buds will not form. You’ll have them in bloom by January if you start now.
Stevia – Remember to take the last pinch by August 1, not later, for flower buds will soon form.
Primula – For blooms in February, sow seed of Malacoides now. Polyanthus and Kewensis types can be divided this month.
Last year’s calla lilies should be repotted in fresh soil.
Other seed sowings for this month can include: cineraria, winter-flowering forget-me-nots (mnyosotis), nemesia, pansies, sweet peas, sweet alyssum, blue lace-flower (didiscus), browallia, calceolaria and fibrous-rooted begonias.
Small plants of bouvardia, Boston yellow daisies, and marguerites should be transferred to 4- or 5-inch pots. Poinsettias should be transferred to the next larger size pot.
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