Cornus sericea L., Red-osier Dogwood

Introduction, neophyte, deliberately planted, rare and thinly scattered.

1950; MCM & D; Inishroosk, Upper Lough Erne.

June to August.

A native deciduous shrub of N America introduced to B & I ornamental gardens in the late 17th century, C. sericea has become rather commonly used in landscaping and amenity plantations for the decorative effect of its many, bare, reddish-brown or blood-red winter twigs. It is also used for ground- and game-cover, particularly in damp woods, hedges and other ground near water and in areas subject to occasional flooding during the last 60 or so years. Given eutrophic wetland conditions, C. sericea readily spreads by suckering and it can form large, dense clonal thickets up to 3 m tall that are capable of suppressing virtually all pre-existing herbaceous vegetation (Kelly 1990).

C. sericea can be distinguished from C. sanguinea by its larger leaves usually having at least six pairs of curved side veins as compared to at most five pairs in the latter. The young twigs of C. sericea are a brighter red in spring and summer (although they turn brownish-red in autumn) and they are often covered in prominent dots. The flowers are also smaller (6-7 mm across) and the berry-like fruit is white rather than purplish-black (Sell & Murrell 2009; Parnell & Curtis 2012).

In Fermanagh, C. sericea was recorded from five sites by Meikle and his co-workers between 1950-3 and it has been found at a further eight stations since then, meaning that it is now thinly scattered across a total of just 13 tetrads, 2.5% of those in the VC. Fortunately, Red-osier Dogwood does not set seed and thus control of this potentially invasive, woody weed ought to be perfectly feasible. In a county with as much damp and wet ground as Fermanagh, C. sericea has the capacity to become a real threat to biodiversity through suckering and layering and therefore planting of it should be strongly and actively discouraged (Kelly 1990).

The New Atlas hectad map shows C. sericea is now widely distributed throughout Ireland and is particularly well represented in the north of the island. It has also spread rapidly in most of lowland Britain as far N as Glasgow and Edinburgh, becoming rarer and more coastal N & E of Inverness.