This section is from the book "The Florists' Manual", by William Scott. Also available from Amazon: The Florist's Manual.
The species best known and most useful is C. scandens and plants are annually raised in large quantities to be used as outdoor climbers. It is a perennial, but it is much better for us to treat it as an annual. As a quick growing plant of fine appearance to cover verandas, summer houses and stumps of trees it has scarcely an equal. It flowers profusely in August and September, but the large, bell-shaped flower is not conspicuous as, in color, it is of little contrast to the leaves. Where people want permanent vines, such as honeysuckles, bignonias, etc., and are impatient of results we recommend the cobaea for immediate effect, or till the hardy vines make a show. When this is done be careful not to let the cobaeas smother the permanent vines when young.
The variegated form of Cobaea scan-dens is a beautiful plant and makes a fine greenhouse climber, but is not of value outside. The variegated sort is always propagated by cuttings which strike root in the sand at any time you have good young shoots ready.
Cobaea scandens is always raised from seed. We sow in March in flats containing two inches of light, sandy soil, and keep in a temperature of 60 degrees. Press the soil down evenly and moderately firm, and press the seeds into the soil, always on edge. No covering is needed; the upper edge of the seed can be even with the surface of the soil. Give them a good watering and keep moist till the young plants are up an inch or two, when they should have plenty of light and be soon potted off singly in small pots.
They grow rapidly, and when five or six inches high we shift them into a 4-inch pot and put a stake two feet long to each one. If not staked and tied they get entangled with each other and it would be impossible to get them apart. There are few of our customers that don't know the cobea and a few hundred are asked for every spring. And when you have to buy it is one of those things difficult to get in satisfactory shape.
 
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