With its 80 or so species, the genusSpiraeais quickly rising up to become a garden favorite.
The species are easy to grow and maintain and there is a wide range of readily availablecultivarsandhybridson the market.
TheSpiraeagenus as a whole has a few distinct identifying physical features.
The Spruce / Evgeniya Vlasova
Each isdeciduous, mostly with narrow, oval-shaped leaves called lanceolate.
They all have many tightly clustered flowers with five sepals and five petals.
These similarities are often as far as it goes when it comes to the genus.
The Spruce / Evgeniya Vlasova
This is great news for designers and gardeners looking for variety in their landscapes.
It can seed easily, take over natural areas, and prevent native plants from thriving.
Water
Keep newly planted spiraea well-watered until they have established themselves.
The Spruce / Evgeniya Vlasova
This method is preferred because the genus tends to developroot rotand overwatering can cause serious issues.
Temperature and Humidity
Spiraea can be winter hardy down to 15 degreesFahrenheit.
Fertilizer
TheSpiraeagenus is not one that feeds heavily.
The Spruce / Evgeniya Vlasova
If it is producing healthy and vigorous blooms, no fertilization may be needed.
If feeding is required, it should only be done annually in the early spring with a slow-release fertilizer.
Types of Spiraea
There are many differentSpiraeaspeciesto choose from.
The Spruce / Evgeniya Vlasova
Below are just a few popular choices available for growing in North America.
Pruning
Any spiraea plant can benefit from a vigorous pruning of old wood.
Cut each stem back, leaving at least five buds on each.
The Spruce / Evgeniya Vlasova
Thin out branches from the middle to improve overall air circulation around the plant.
Remove any suckers, and generally tidy up the plant.
Most species should be pruned only after flowering is finished for the season.
These can be remedied with a good blast of water or horticultural oil.
Fungicides can help with that problem.
Root Rot
Poorly drained, overly wet soil can cause root rot.
Improve drainage and let the soil dry out between watering.
Improve the growing environment, use drip irrigation, and treat the plant with a fungicide.
That depends upon the cultivar, but many of them can live up to 20 years with proper care.
Japanese Spiraea.Western Pennsylvania Conservancy.
