May 2017 in the Garden

What can we expect in the garden this May? A few April flowers, I think. This spring is going down as one of the wettest and coolest on record, and this has pushed back flowering considerably. Even so, there is a tendency among plants to catch up, especially the later flowering kinds, so there won’t be too many surprises in May.

In UBC Botanical Garden, the Cistus clan are dependable of May bloomers. The genus Cistus comprises about twenty species of hairy and sticky-glandular, heliophytic (sun-loving) shrubs from the Mediterranean region. Like some poppies, cistus flowers display crumpled aestivation (aestivation describes the way flower petals are packed in the bud). Creases from the packing are often still visible on the expanded petals. The five-petaled flowers are radially symmetrical and usually disk-like when fully open, either monochrome white to light purple, or the base of each petal is marked by a dark purple spot and/or yellow spot. The flowers are individually short lived, but are often borne over many months starting in May. At the centre of the flower is a small boss of yellow stamens. Cistus is commonly known in books and plant lists as “rock rose”—but most people simply call them cistus. They are often short lived in Vancouver’s wet winter climate, but there are usually several species and hybrids in the E.H. Lohbrunner Alpine Garden, where the drainage is excellent and excess moisture seldom persists.

Cistus x lenis ‘Grayswood Pink’

Among the most beautiful is Cistus x lenis ‘Grayswood Pink’, a wide-spreading, relatively low grower, with lax stems, small leaves and small pink flowers. The leaves are grey-green and wrinkled. The youngest stems are reddish, as are the flower buds, and the 4-cm flowers are silvery pink, each petal slightly darker at the tip and fading to white at the base. Another, C. albidus, is named for the whitish hairs that clothe all parts of the plant (alba = white). It is native to southwestern Europe and western North Africa, where it grows to about 1.2 m tall and wide. This species is particularly robust, with stout stems and green wrinkled leaves. The upright leaf posture exposes the grey-green undersides and the greyish stems, making an overall impression of greyish green. The flowers are bright, lavender pink, about 5 cm across, held in terminal clusters of up to nine flowers. Both cistus are located in the African section of the Alpine Garden. One of the most unusual Cistus species is found in the European Woodland behind the Roseline Sturdy Amphitheatre. The laurel-leaved cistus, C. laurifolius, is a particularly tough, long-lived shrub. It is usually upright, 1 to 2 m tall, with resinous stems and dark, almost black-green leaves. The flowers are white, 4 to 5 cm across, emerging from globose, reddish buds. Rounding out the collection in the Alpine Garden is C. inflatus which has white-hairy, aromatic, sticky-resinous new growth and 5-cm white flowers. Prominent, soft white hairs also accompany the flower buds, which appear somewhat inflated. Plants can be found in the European section, where they grow into neatly rounded bushes about a meter tall and across.

More photos can be found in our Forums.

Submitted by Douglas Justice, Associate Director, Horticulture & Collections, April 27, 2017

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