Spirea
Lynda Ellis, Anoka County Master Gardener
Spirea is a species of shrub. The most common spirea found in Minnesota is called Spiraea japonica, also known as Japanese meadowsweet. It is a low-maintenance deciduous shrub with showy flowers and green or yellow leaves. Spirea is a zone 4-8 plant. Perfect for Minnesota.
Spirea comes is various sizes depending on the cultivar. The shrub is typically two to three feet high and three to five feet wide, but some cultivars can grow five to six feet high and wide. It falls into two categories: spring-blooming and summer-blooming varieties with white or carmine flowers.
Both the flowers and the foliage for spirea come in many different colors and combinations. The flowers can range from the popular white and pink flowers to the more dramatic red and purple colors. The foliage can range from the traditional green to yellow, lime, and even burgundy and purple!
What light is required for this shrub? Spirea performs best in full sun, where it produces more blooms, vibrant color and brighter fall foliage. Plants can take light shade, with spring bloomers being more shade tolerant than summer bloomers. Spirea can be used as specimen planting or as a group for rock gardens. Mass or group it in a shrub border or use it in foundation planting.
To plant a spirea, dig a hole slightly deeper than the root ball and two times wider than the root ball. Remove the plant from the nursery pot and loosen the soil around the roots. Set the plant in the hole with the top of the root ball at or slightly above soil level. Backfill the hole with soil and tamp down slightly to remove air pockets.
Pruning spirea every year encourages an optimum display of flowers. Prune summer-blooming varieties in early spring and prune spring-blooming varieties after flowering is over. Spirea prefer average fertile soils with medium moisture.
Spirea are deer resistant and tolerant of erosion, clay, and air pollution. These shrubs can be invasive with aggressive propagation. Remove spent flower heads to prevent this and encourage new blooms.
In traditional Chinese medicine, young leaves, fruits, and roots of this shrub are used as a diuretic, and pain reliever as well as detoxification and treatment of coughs, headaches, and toothaches. Consult with your doctor before using any plant parts medically.
Personal Experience: Several years ago, I bought my first spirea. It was a summer-bloomer with carmine flowers and yellow leaves. I planted it in fertile soil in full sun. It has now reached its mature size, about three feet high and wide. I cut it back most years, taking off four to six inches all around.
There is fertile ground near it, and I noticed another feature of spirea; it has babies! The small spirea were varied; some had green leaves and some had yellow. I dug them up and planted them; now I have a spirea hedge. People to whom I donated plants preferred yellow leaves, so now my hedge has more green leaves.
Try one spirea or a bunch. You will not be sorry!