7 x edible shrubs for improving urban biodiversity

In these blog posts, Maike van Stiphout (landscape architect and author of First Guide to Nature Inclusive Design) and Jeanne Tan (architecture writer and content editor) delve into the world of shrubs, sharing the beauty of this under appreciated group of plants which are ideal for urban nature, urban biodiversity and urban food forests. First up is Sloe famed for its ethereal white blossoms and its plum-like fruit. Supporting a wide variety of wildlife, the low maintenance Sloe shrub or hedge is a firm favourite for improving urban biodiversity all year round.

  1. Sloe or Blackthorn (Prunus spinosa)

Native to the Netherlands, Sloe is an ancient shrub that supports a wide variety of wildlife, making it one of our favourites to plant in urban landscapes to improve biodiversity all year round. It’s famed for its delicate white blossoms and edible dark purple fruit called sloes. Low maintenance Sloe shrubs suit rather wild landscapes and gardens and are excellent as hedges. It thrives in full sun but can tolerate some shade.

After long Dutch winters, a blossoming Sloe in March is a spectacle to celebrate – spring is on the way! They transform in early spring from a thick mass of thorny branches into ephemeral clouds of delicate white blossoms. Importantly, at this time when there’s little food available, Sloe blossoms provide precious nectar and pollen for bees, bumblebees and butterflies. After the blossoms have been pollinated, the fruit appears. 

Later in the season Sloe becomes a favourite foodplant for the caterpillars of moths and butterflies, in particular the black hairstreak (Satyrium pruni) which lay their eggs almost exclusively here. This butterflie is extremely rare in The Netherlands.

Sloe provides an ideal nesting habitat for birds – especially with caterpillars, an important food source, within easy reach. Although Sloe is deciduous, its dense, thorny branches offer shelter to birds and other wildlife against urban predators all year round.

Come autumn, the small oval leaves turn orange and the clusters of fruit ripen into a rich dark purple – a beautiful sight. Resembling mini plums, sloes are the predecessor of our cultivated plums. Try to spot birds such as thrushes feasting on them. If you’re going to harvest some, don’t be tempted to eat them straight away – they’re astringent and tart. Traditionally sloes are prized for making jam and wine and infusing liqueur such as Slivovitsj.