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Plant Highlight: Grevillea lavandulacea ‘Penola’

February 2025

By Brian Kemble


Family placement and area of occurrence

Grevillea is a large genus (about 360 species) in the Protea Family (Proteaceae). The great majority of the species are from Australia, but a few come from nearby islands (New Caledonia, New Guinea and Sulawesi). They are mostly evergreen shrubs, though a few of the largest ones are trees. Much hybridizing has been done in the genus, and new hybrids are continually finding their way into horticulture, but one of the tried-and-true cultivars is Grevillea lavandulacea ‘Penola’.

The home range of Grevillea lavandulacea is in southeastern Australia, in the western part of Victoria and the eastern part of South Australia. It varies in habit from low-growing prostrate forms to shrubs as much as 5 feet tall (1.5 m), and the cultivar ‘Penola’ is at the larger end of this spectrum, attaining a height of 4 to 5 feet (1.2 to 2 m).

About the plant

The narrow gray-green leaves of Grevillea lavandulacea vary from .2 inch to 1.57 inches long (5 to 40 mm), with a width of .02 to .4 inch (.5 to 10 mm). Our plant of L. lavandulacea ‘Penola’ at the Ruth Bancroft Garden is a little toward the small end of this wide range, with leaves up to .79 inch long (20 mm) and .047 inch wide (1.2 mm). If the leaves were flat, they would be wider than this, but they are rolled under at their margins, narrowing their profile. The upper leaf surface has a dark green background overlain with matted white hairs, and the lower surface is white-felted and much paler. The leaf margins are entire (not scalloped like those of lavender, whose somewhat similar appearance gave rise to the species name lavandulacea), and the tip narrows to a sharp point.

About the flowers

While some species of Grevillea have flowers in dense clusters, those of G. lavandulacea ‘Penola’ come in small clusters of 2 to 10, held on short side shoots along the branches. They might be lost among the foliage, except that the leaves are so narrow, and the flowers so numerous (with their red color contrasting dramatically with the grey-green of the leaves), that they make quite an impression. Because the clusters have few flowers, these are on full display, and their curlicue appearance is quite apparent. Each flower is bright red at the base, with two calyx lobes that are curled under at their tips, fading to pink and then white toward their ends. Between them is a red pistil that arches out well beyond the rest of the flower, with a small club-like tip. Tucked between the calyx lobes and the lower part of the style are the small pollen-bearing anthers. Not counting the pistil, the flower is only about .4 inch long (1 cm), but when fully extended, the pistil doubles this length. The slender pedicel (the stalk of the individual flower) is also about another centimeter long. As is common in the Proteaceae, the stigma at the tip of the pistil initially functions as a “pollen presenter”: as it uncurls and extends outward from the rest of the flower, it brushes against the anthers and gets a dusting of pollen; when it is fully extended, the pollen is in position to be transferred to visiting pollinators. Later, the stigma becomes receptive, and it can then receive pollen brought by a pollinator from another flower. Late winter into spring is the flowering season for this plant, and at the Ruth Bancroft Garden, we generally have flowers in February through April, with the last flowers ending sometime in May.

About the fruits

A successfully pollinated flower of G. lavandulacea ‘Penola’ produces a downy follicle about a half-inch long (13 mm) containing a single seed. The dried remains of the pistil persist, jutting out from the tip of the follicle. At maturity, the follicle splits open along one side, releasing the single seed within.

Growing the plant

Grevillea lavandulacea ‘Penola’ is not difficult to grow if given plenty of sun and adequate drainage. As with other plants in the Proteaceae, fertilizers with significant levels of phosphorus should be avoided. Members of the family are commonly found in soils with low levels of this element, and they can easily overdose if they get too much. This is a drought-tolerant species, and it can withstand winter lows down to about 20° F (-7° C), though not sustained freezing weather.

Click here to find out more about what’s in bloom at the Garden.