Grevillea banksii: A Striking Ornamental Shrub for Sun or Shade

Grevillea banksii is an eye-catching ornamental shrub belonging to the Proteaceae family. This species is native to Queensland, Australia, and is commonly known as Red Silky Oak or Kahili Tree (in the Hawaiian Islands). It displays an erect, bushy to spindly growth habit, capable of reaching heights of up to 20 feet, resembling a small tree.

The plant’s stunning red flowers add a vibrant touch to the landscape, with a prolonged blooming period during spring and summer. Grevillea banksii features predominantly divided leaves, consisting of four to twelve narrowly elliptic to linear lobes measuring 50–180 mm in length and 5–15 mm in width, characterized by edges turned down or rolled under.

The flowers are arranged in cylindrical groups at the ends of branches, with individual flowers supported by pedicels 3–10 mm long along a rachis 50–120 mm in length. The flower colors range from creamy-white to bright scarlet or crimson, lending a truly exotic appearance. The pistil typically measures 32–50 mm in length and is usually glabrous.

**Cultivation of Grevillea banksii:**

Sunlight and Soil Requirements: Grevillea banksii thrives in locations receiving full sun or partial shade. It adapts well to various light conditions.

Planting: Choose a planting time in either spring or fall. Select a spot that offers full sun or partial shade. Ensure the soil is well-drained and slightly acidic. Prior to planting, amend the soil with compost or well-rotted manure. After planting, provide the plant with a generous amount of water.

Watering: Regular watering is crucial for Grevillea banksii, especially during hot and dry weather. Aim for deep watering sessions to reach the roots, allowing the soil to slightly dry out between waterings.

Fertilizing: Apply a balanced fertilizer once a month during the growing season. Opt for a slow-release formulation, such as a 10-10-10 fertilizer, to provide consistent nourishment.

Pruning: Grevillea banksii generally requires minimal pruning. Remove any dead or damaged growth in the spring to maintain the plant’s health. Dividing the plant every 3-5 years promotes its vitality.

Pests and Diseases: This species is typically resistant to pests and diseases. However, keep an eye out for aphids, spider mites, and scale infestations. Promptly address any signs of pests or diseases by employing suitable pesticides or fungicides.

Mulching: Apply a 2-3 inch layer of mulch around the plant to retain moisture and suppress weed growth.

Deadheading: Pinch off spent blooms with your fingers to encourage continuous flowering.

Division:

Every 3-5 years, divide Grevillea banksii to ensure its vigor. Gently separate the roots after digging up the plant and replant the divisions in well-drained soil.

Propagation: Grevillea banksii can be propagated through either seed or cuttings. While seed germination may be erratic, propagating through cuttings is often recommended. Take 4-6 inch cuttings from healthy, non-flowering stems during spring or summer. Dip the cut ends in rooting hormone and plant them in a well-drained potting mix. Maintain moisture in the potting mix and place the cuttings in a warm, bright location. Rooting should occur within 4-6 weeks.

With its striking appearance and exotic flowers, Grevillea banksii can become a remarkable addition