Recent trials in Liguria suggest a promising future for several species of Asclepias due to their very rapid growth and flowering and low labour input during cultivation. Asclepias curassavica, a native of South America, is an evergreen shruby (partially lignified) perennial that will grow to about 90cm. It produces abundant flowering branches for cutting with clusters of red-orange flwers in terminal and axillary clusters. A cultivar exists with yellow flowers. Asclepias curassavica also makes an excellent plant for borders and meadow gardens and they attract butterflies.

In a typically Mediterranean climate Asclepias curassavica can be grown under protection or in the open. If it does freeze to the ground plants will usually come back in the spring. In cooler climates it is grown as an annual. When grown under protection at a minimum of 12°C, plants flower earlier from end of March to mid April. While the natural flowering period from May/June to October/November, the main flush is in the spring. The plants are dormant in the winter and by making an early pruning in February, the number of flowering branches can be increased to 56/plant/year. The flowering branches are about 50-60 cm long and their shelf-life is about 8-10 days. Silver thiosulphate prolongues shelf-life but further experimentation on post-harvest treatments is considered necessary. Flowers are composed of a ring of downward pointing sepals that form thecalyx, a ring of petals that form the corolla upon which there is an extra ring of appendages that form the corona. Asclepias curassavica is mainly grown from cuttings that will ordinarily root in 4-6 weeks. In general Asclepias species can be propagated from seed (germination will best take place at 16-18°C) either in the autumn or the spring. If sown early enough the resulting plants will the same year. Ideally, plants are grown at temperatures no lower than 10°C. They prefer a rich moist soil but one that is not heavy. Plants can be cultivated in greenhouse or outside in sunny positions but protected from stong winds. Frequent watering,is required in the spring and summer but kept to a minimum in the winter. When grown outside, especially the taller growing species will need some form of staking.

Asclepias tuberosa is a rustic perennial that grows to about 60cm. It usually dies back in the winter and re-sprouts from its underground tubers. It produces bright orange or red flowers in clusters followed by attractive pods. It is a useful plant in mixed borders, meadows and natuarl areas. If clumps of tubers are placed in a coldstore at 3°C for at least 3 months, when they are later transplanted under greenhouse conditions they will produce flowering branches in 70-80 days. It is important not to damage the roots. To produce pot/container plants, potting is normallly made in the spring.

Other species such as Asclepias specioss grows to a height of 70-80cm and produces flower clusters 3-10cm in diameter with violet flowers that are good in floral compositions. Asclepias fruticosa (renamed Gomphocarpus fruticosa) is better known not for its umbels of white flowers but for the large blown up fruit. These grow to about 8cm with a silvery green skin that makes them interesting in floral decoration. Asclepias incarnata grows is a semi-acquatic soecies that grows to 30-50cm and flowers from July to September. It produces striking pink flowers.

The genera Asclepias contains some 200 different species that originate mainly in N.America but also in S.America and Africa. The roots are often rhizomatous or tuberous and the stems of most species produce a milky white sap that is poisonous if eaten and irritating to the skin. "Colture Protette", fax 051 6575856 E-mail: cp@gce.it