The garden varieties of these well-known plants are probably hybrids. They have been decidedly deposed from their former popularity by the carpet and subtropical bedding, but of late we see many more verbena beds, and few plants can be prettier. The varieties we get from seed are now so good that little attention is paid to named sorts and the trouble of keeping them over winter is dispensed with.
If you wish to propagate fine varieties they should be shortened back about September 1, and kept watered. By the end of the month there will be plenty of nice, fresh cuttings, and only a quick, tender growth should be used. Put the cuttings in the propagating house, or what is as good, in flats with some soil in the bottom and sand on the surface. Keep the flats in a coldframe and keep moist and shaded from the sun. They will take a copious watering every day.
Verbenas will stand quite a frost, but it is not well to let the cuttings freeze. When rooted they can be kept in a cool but light house and be kept in the flats till after New Year's, when they can be potted off into 2 1/2-inch pots and kept in a temperature of 50 degrees. You will soon get plenty of cuttings which root very freely, and before spring you can have a large stock. Plants propagated from cuttings want to flower early and those propagated in February and March will want at least one pinching.
Seed is now used by most florists for their stock of verbenas. It has the advantage of producing good, healthy plants free of all disease, and when planted out they are sure to do well and make a most satisfactory flower bed. Sow the seed in February, and pot into 2-inch pots as soon as they are up an inch. You can usually get a cutting from an early sowing if you wish. If not, just pinch out the tip of the plant. A temperature of 45 to 50 degrees will suit these seedlings, but they should be given full light.
There is no place equal to a mild hotbed for the verbenas, so about the middle of April plunge the small pots in a few inches of soil in a mild bed. They will grow very fast, and quickly get rooted in the soil of the bed, which will delay their flowering, particularly the seedlings, and for that reason they should be lifted, the roots rubbed off, and put back in the same spot. That will check their growth and induce them to flower. Most of our customers want to see the colors, so it is important to get them into flower.
Verbenas are much troubled with greenfly, and they should be perfectly clean when they go into the hotbed. If affected with the rust so troublesome to the verbena when we grew named varieties, throw them away; it is much cheaper to buy clean stock.
Verbena venosa is a true species and is always raised from seed. It can be sown in February and grown along in flats. Its beautiful and abundant blue flowers make a fine bed either alone or in combination with a silver-leaved geranium.
Verbenas can be planted out early in May. A slight frost will do them no harm, but our customers seldom look for them till the end of May.