The hydrangea, rhododendron, and lilac have all become very popular flowering shrubs for people to have in their gardens. This is because they have long-lasting blooms and can serve a variety of landscape functions. Some examples of these functions are mass plantings, perennial borders, groundcovers, and informal hedges. If you are only familiar with the traditional bridal wreath spirea, you will be surprised to know that there are now versions of it that are easier to take care of and have more vibrant foliage. This means that they are interesting to look at even when they are not blooming.
SPIREA BASICS
Zones:
Some varieties of this plant are more tolerant to extreme temperatures than others. Most of them can withstand harsh conditions in zones 4 through 8, but some can survive in even harsher climates.
Size range:
The plant can grow to be 1-8 feet tall and up to 6 feet wide.
Light exposure:
For the best foliage color and flower production, spirea should be given full sun (at least 6 hours of direct light daily).
Soil preference:
Soil that is well-drained and neutral to slightly acidic is best for this plant.
Bloom period:
The two types of spirea bushes are those that bloom in the spring and those that bloom in the summer.
Growth rate:
Moderate to fast.
Wildlife benefits:
Attracts bees and butterflies; deer resistant.
Is spirea invasive?
There are some species of spirea that can spread their seeds aggressively in certain areas of the country. You should check with local experts to see what type of spirea would be best for the region you live in. Some newer cultivars, like the Double Play Doozie®, have been bred to be seedless and not spread as easily. Alternatively, you could also plant sweetspire or summersweet.
TYPES OF SPIREA
Japanese spirea (Spiraea japonica):
There are many types of Japanese spirea, which differ in size, flower color, and leaf color. These plants produce large numbers of white, light pink, rosy red, or purple flowers in late spring and summer. Some varieties of Japanese spirea are very small, while others can grow to be five feet tall or more. Most varieties have leaves that are green or blue-green in color, but some have yellow or chartreuse leaves that change color over the course of the season.
Bridal wreath spirea (Spiraea prunifolia):
This plant is most recognizable by its tiny carnation-like double white flowers that cover the bare branches in early spring. Bridal wreath is one of the largest of the spirea species, reaching 4 to 8 feet high and 6 to 8 feet wide. It has loose, arching branches that give it a fountain-like effect. In fall, the finely serrated green leaves turn shades of yellow, red, and orange.
Nippon spirea (Spiraea nipponica):
The Nippon spirea is an erect, rounded shrub that grows to 4-5 feet tall and wide, with graceful branches hanging over the sides. In late spring, the shrub is covered in small white flowers that cluster together like a bouquet. The deep blue-green leaves are a nice contrast during the summer months.
Birchleaf spirea (Spiraea betulifolia):
. This shrub grows 3-4 feet tall and wide, is compact and rounded, and has white flowers that appear in early to midsummer. It is most colorful in autumn, when the dark green, birch-like leaves turn rich shades of red, orange, and purple.
Early spirea (Spiraea thunbergii):
A spirea that is 3 to 5 feet tall, this one blooms early in the spring. The white, umbrella-shaped flowers come out on slender, arching branches. The foliage is a pale green and is finely textured. In the fall, the foliage takes on yellow and orange tones.
How to grow Spirea bushes
After your plants have rooted, it is easy to take care of your shrub with some basic care.
This section contains general care information that may be of use to you.
Note that YMMV: different cultivars will require different needs.
Hardiness zone
Spirea shrubs can be grown in lots of different environments, but they thrive best in zones 4-10.
It can survive in different types of weather, but it will do best in moderate heat with bright, sunny weather.
You may have to change your plans to match the suggested zone.
An example of what to do if it’s too cold would be to use mulch or row covers to insulate the roots. An example of what to do if it’s too hot would be to use artificial shade to block out the sunlight.
In order to make your plants happy, you need to change their environment depending on the local climate. Your plants will then reward you by blooming beautifully.
Soil
You should use garden soil that is high quality and drains well. To help improve drainage, mix in some sand.
If the soil around your shrub clumps or drains poorly, water can pool and lead to rot or fungus. Use soil made for shrubs, if possible. Amend it to help get the pH to an acidic level. Bone meal will be excellent for new plants.
pH level
Chlorosis is a condition that can affect spirea growth if the soil is too basic (alkaline).
make sure the pH is acidic to encourage fuller blooms and bigger foliage. You can adjust the pH using soil amendments such as limestone.
Depth
The right depth to plant your cutting at will differ depending on where you’re getting it from. If you’re taking it from the garden, make sure the roots are buried firmly in the soil.
Spacing
Space them out adequately to ensure they get the space they need to grow. They grow wide roots that will space themselves out.
Cultivars should be placed at least 12 feet apart.
If you have other plants nearby, they may compete for resources.
Plant food
Spirea plants will do better if you feed them with a good quality plant food. Use half the amount of a well-known brand of general-purpose fertilizer that has a NPK balance of 10-10-10.
Apply half the amount of fertilizer that is recommended and observe how your plant reacts. If it seems unharmed, then you can apply the full recommended amount.
Apply a time-released liquid fertilizer in early spring when plants are most actively growing.
By ensuring your Spirea has enough nutrition, you will create the conditions necessary for it to produce flowers during blooming time. Overfeeding your shrub is unnecessary and may even be harmful – plain, basic fertilizer will work just fine.
Temperature
The type of spirea you are growing affects how tolerant it is to different temperatures. Spirea can generally tolerate cold temperatures down to 5 degrees Fahrenheit and heat upwards of 80 degrees Fahrenheit.
Make sure to look up the specific plant requirements to see if it can handle the temperature range in your area. Most plants will be able to tolerate the weather if you live in zones 4 through 10.
Watering
This plant can survive long periods without water, making it a good choice for regions that don’t get much rain.
Water your plant very well when the ground is close to being dry. Doing this regularly will help the plant become strong until it has strong roots.
During their growing season, they need more water, but when they get older, they need less.
Humidity
Spirea does not have a preference for humidity, as long as the humidity levels are moderate at 50%.
Leaves that are not pruned can cause fungus because of the high humidity levels. By pruning the leaves, you can eliminate the fungus. When you prune the leaves, you are also removing the foliage, which can help alleviate pooling.
Sunlight
Spirea shrubs require full sun for ideal growth.
If you want to grow gorgeous pink or white flowers during the spring or summer, give them the sun they want!
When determining where to plant your shrubs, keep in mind that those that bloom in the spring will do best in partial shade, while those that bloom in the summer will thrive in full sun.
While spring flowers typically grow best in cooler temperatures with partial shade, those in bloom during summertime enjoy hotter weather and full sunlight.
Although it’s not a make-or-break factor, the location you choose to plant your flowers can have some impact. Flowers planted in full sun typically produce more blooms and brighter colors, especially in the fall.
Pruning
Spirea only needs minimal upkeep such as pruning dead leaves and spent flowers.
Pruning dead leaves and flowers helps to encourage new growth and Keep bugs off your shrubs. Spirea benefits from yearly maintenance.
The soil level should be checked with a monitor to see if nutrients are lacking.
Amend it if so.
Pruning on a regular basis is beneficial as it helps to foster more growth in the stems. By adhering to a pruning schedule, you can optimize the amount of flowers produced.
The best time to prune Spring flowering Spirea is immediately after they finish flowering. This will help to keep the shrub from getting too large.
Shrubs should be pruned in the winter after they get spent. Wood should be trimmed often to keep the plant in shape. Bloomers will easily outgrow their size, so they should be pruned regularly.
You can cut back the shrub by up to a quarter of its original size when it goes into dormancy for the winter.
Cutting the plant back after it has flowered will help to promote more flowers and foliage growth.
Overwintering
Spirea is not something you need to worry about during wintertime. If it is grown in the right zone, you don’t need to do anything special to prepare it for winter.
You will need to mulch or use row covers for younger plants. This will help protect the roots from the cold weather. Two to three inches of mulch is all you need.
For very low temperatures, use row covers or plant wraps.
SPIREA CARE
Fertilizing:
You don’t need to give spireas a lot of fertilizer, just some controlled-release fertilizer in the spring. That should be enough to last the whole season.
Watering:
Water newly planted spireas regularly until they have become established. Mature spireas can tolerate periods without water and only need to be watered when the soil has become dry. Spireas don’t like being in wet soil, so avoid watering too frequently.
Pruning spirea:
You can prune spireas liberally if needed, to maintain their shape and remove any dead or broken branches. It’s best to do this in late winter or early spring, when your plants are dormant. Giving spireas another lighter pruning after they bloom in spring or early summer will promote new blooms and invigorate foliage growth. Because spireas are fast growers, they will recover quickly.
Pests and diseases:
Although spirea plants don’t usually have any significant problems with pests or diseases, they can sometimes be affected by the same pests and diseases as roses. These include leaf spot, powdery mildew, and aphids.
Companion plants
This bush can be picky with its neighbors.
Spirea uses a lot of nutrients from the soil which quickly outcompetes other plants. Spirea can also grow up to 8 feet wide, which means it shouldn’t be planted near other plants in the first place.
Use plants that don’t need a lot of nutrients to do well as companions for your other plants. Examples of these are junipers, weigela, and viburnum.
Ornamental grasses, asters, and heucheras are also good choices to grow with Spirea plants.
Don’t plant with
Shrubs shouldn’t be planted next to other plants that would compete for the same nutrients.
They should be planted 10 feet apart to allow for plenty of room to grow.
Make sure to give your Venus flytrap and other carnivorous plants plenty of space from other plants, as they may suffer from a lack of nutrients if they are too close to other plants.
This is especially true if your soil is poor. Giving them more space is essential.
SPIREA LANDSCAPING TIPS
- Low-growing mounded varieties work nicely in smaller gardens and can be used to form shrub borders, groundcovers, low hedges along pathways, and fillers in the perennial garden.
- Spireas are also attractive additions to butterfly and cottage gardens.
- Dwarf varieties can be grown in containers on a patio or balcony.
- Mix in landscape beds with other flowering shrubs like abelia and weigela.
Growing indoors
It’s not possible to grow this shrub indoors because it’s too big.
When your plant gets too big, you need to move it outdoors.
The roots of the plant will get too big for the container it is in and will need to be moved to a spot in your garden.
It’s more work to start outside and then come in, so why not just start inside in the first place?
It’s not necessary to make things difficult for yourself unless your climate is cold.
