Grevillea ‘Penola’ is a popular evergreen shrub, valued for its unique appearance and adaptability in various garden settings. Its vibrant floral display and distinctive foliage make it a favored choice for visual interest and ecological benefits. This hybrid offers ornamental appeal and resilience, making it a desirable addition for many gardeners.
Grevillea Penola Overview
Grevillea ‘Penola’ is a compact, mounding evergreen shrub, typically 4 to 5 feet tall and 6 to 8 feet wide. Its fine-textured, narrow, gray-green leaves often appear silvery due to fine hairs.
Its most notable feature is an abundant display of rosy-red or pink, spider-like flowers. These unique blooms, appearing in clusters, have a bright red base, curling calyx lobes, and an arching red pistil. Peak flowering occurs from late fall through spring, sometimes extending into May, contributing to its appeal.
Planting and Ideal Conditions
For optimal growth and flowering, select a site with full sun exposure. While partial shade is tolerated in hotter climates, direct sunlight for most of the day is preferred. Adequate air circulation is also beneficial.
It requires well-drained soil and is intolerant of standing water. It adapts to sandy, loamy, and clay soils, provided they are not waterlogged. Grevillea ‘Penola’ prefers slightly acidic to neutral pH.
A critical consideration for Grevillea ‘Penola’ and other plants in the Proteaceae family is their sensitivity to phosphorus. Australian native plants, including Grevilleas, have evolved in low-phosphorus soils and are highly efficient at nutrient uptake, making them susceptible to phosphorus toxicity from conventional fertilizers or rich soils. Therefore, it is advisable to avoid high-phosphorus fertilizers and amend planting sites with low-phosphorus or native plant-specific soil amendments. This plant is hardy in USDA Zones 9-11 and can tolerate winter lows down to approximately 20°F (-7°C), though not prolonged freezing conditions.
Ongoing Care
Once established, Grevillea ‘Penola’ demonstrates remarkable drought tolerance, requiring minimal supplemental water. During the initial establishment phase, typically one to two years after planting, regular watering is beneficial, especially during dry periods or heatwaves. However, mature plants prefer drier conditions, particularly during summer, and should not be overwatered.
Regarding nutrient provision, Grevillea ‘Penola’ generally requires minimal or no fertilization due to its sensitivity to phosphorus. If feeding is deemed necessary, only use fertilizers specifically formulated for native plants or those explicitly labeled as low-phosphorus. Excessive nitrogen can lead to lush foliage at the expense of flower production.
Pruning is beneficial for maintaining the plant’s shape, controlling its size, and encouraging bushier growth and more prolific flowering. The best time to prune is immediately after its main flowering period, which typically occurs from late fall through spring. Avoid severe pruning of established plants, as they may lack the reserves to recover. Grevillea ‘Penola’ is generally resistant to most pests and diseases, though some sources mention susceptibility to scale and spider mites.
Landscaping Applications and Benefits
Grevillea ‘Penola’ offers diverse landscaping applications due to its attractive form and resilience. It serves effectively as a specimen plant, providing a focal point with its unique foliage and vibrant blooms. Its dense, spreading habit makes it suitable for mass plantings, creating impactful visual displays or serving as groundcover on banks and slopes for erosion control.
The shrub’s moderate size and dense growth also make it an excellent choice for informal hedging or screening, providing year-round interest and privacy. It performs well in containers, allowing for placement on patios or other limited spaces, though container-grown plants may require more frequent watering than those in the ground.
Beyond its aesthetic appeal, Grevillea ‘Penola’ provides ecological benefits. Its nectar-rich flowers are highly attractive to native birds, particularly hummingbirds, and beneficial insects like bees and butterflies, contributing to garden biodiversity. This plant is also noted for its deer resistance, making it a practical choice in areas where deer browse is a concern.