Grevillea is a plant of shrub-like origin originating from Australia that produces very showy flowers, without petals, formed by a tubular calyx and an elongated and curved stylus.
This plant belongs to the Proteacee family and has more or less dark leaves, depending on the variety; usually these leaves also have a slight down. In places of origin it can also reach 10 meters in height with a crown of 2/6 meters.
The flowers can be of different colors, pink, white or orange, like that of the robust variety, which, however, will hardly produce if cultivated in a vase.
The leaves are pinnate of intense green color covered by a silky hair. As soon as they come out they are light bronze in color.
Grevillea plants should be placed in very bright places, but protected from direct exposure to sunlight which could ruin them, especially during the hottest hours of summer days. It is a plant that prefers warm climates and does not tolerate cold temperatures, therefore, it must be grown at home at a fairly constant temperature. If it is placed outdoors, it must be carefully repaired because it would not survive the rigors of winter.
The best temperature for Grevillea specimens is around 22 degrees in summer, while in winter it can range from 7 to 13 degrees.
For a good growth of these plants, the soil must be moist and must be left to dry between one watering and another because the plant of grevillea does not tolerate water stagnation. When it is very hot, water is sprayed on the foliage with constant nebulisations that allow the plants to have an ideal habitat. Watering must be abundant from April to September. In autumn and winter, it is watered every two weeks, without exceeding.
During the growing season, a few drops of liquid fertilizer are added to the water every three to four weeks.
For the planting of these plants it is advisable to choose a soil that has an excellent drainage, so it is good to prepare a peat mixture and neutral or acid reaction sand, without limestone. Grevillea plants do not tolerate excess moisture and it is important to check that the chosen soil is the one indicated for their cultivation.
It can be sown in March April in pots filled with a mixture of peat, non-calcareous garden soil and sand in equal parts at a temperature of 13 - 16 degrees. When the plants are large enough to be handled, they are planted in individual pots. In April - May cuttings are taken five to seven centimeters long from the side shoots with a portion of the woody branch. The cuttings are planted in non-calcareous compound. The jars are covered with transparent plastic bags and held at 21 degrees centigrade. The rooted cuttings are repotted and kept in the shelter until the spring; they stay in May.
In April irregular and cold branches can be cut.
Grevillea: Pests and diseases
Plants of this type are quite resistant to the attack of pests and diseases, but it can happen that scallop scale insects attack the leaves, which turn yellow and fall. It is good to check if you notice any signs of this type of problem, to intervene quickly, or eliminate the parasites with a cotton pad or, if the attack is rather massive, through the use of systemic products that guarantee the elimination of the problem. Excess moisture can lead to dangerous rots.