Spirea is a vigorous-growing deciduous shrub that is regularly used as a border in the home garden. When considering the addition of spirea to the landscape, keep these steps in mind on how to plant and grow this versatile shrub.
Step 1 – Choose Spring- or Summer-Blooming Spirea
This may seem an unnecessary consideration, but when deciding on which plants to place in the garden, the right choice may depend on what other flowers are in your garden. Choosing a species and variety of spirea that blooms in spring or summer may be appropriate to add variety to your garden.
Step 2 – Select Spot for Planting
Spring- or summer-blooming spirea plants and shrubs like full to partial sun. Garden experts say that they’ll tolerate medium shade, but bloom best with full sun. As for soil type, a sandy loam to clay loam is preferred. To be sure, test the soil pH with a kit. The range should be in the 5 to 7.5 soil pH level. Also, make sure the soil is well-drained. If the soil pH test showed a poor soil, amend the soil with a mixture of part native soil and part organic soil amendment or compost.
Step 3 – Dig Hole for Planting
Depending on the number of spirea to plant, dig holes according to spacing requirements listed on the container tag. Some spirea grow to heights of 2 to 10 feet and from 2 to 20 feet wide.
Generally speaking, space them so they’ll have sufficient room to reach their mature size. Dig the hole twice as wide as the root ball and of a depth similar to what it had in its container.
Step 4 – Remove Spirea from Container and Plant
If the spirea is in a container, tap the bottom and sides to gently loosen it. Then remove the plant and untangle pot-bound roots with fingers. A utility knife may be needed to score tough fibrous roots. Set the plant in the hole and fill in with soil. Make a water well for larger shrubs. Finish planting by thoroughly watering.
For balled and bur lapped spirea plants, undo the fasteners and roll back the top of the burlap, tucking into the hole after positioning. Garden experts recommend complete removal, if possible, of synthetic burlap. Otherwise, use utility knife to score slits in the synthetic burlap so roots can grow into the new soil. The next steps of water well for larger shrubs, mulching and watering are the same as for container spirea.
Note that spirea can tolerate a bit of drought, but they prefer a regular watering schedule. Water deeply and less frequently and water at the base, never directly on the foliage.
Step 5 – Fertilize as Needed
For the first growing season, be sure the spirea gets sufficient fertilizer, one with phosphorus content. As plants mature, they can be fertilized annually. Always pay attention to the grower’s recommendations as to type and frequency of fertilizing.
Step 6 – Pruning Requirements
There are two reasons to prune, according to spirea experts. First, prune old dead wood to increase air flow and reduce disease risk, and second, to prompt new growth which increases flower production. Prune minimally in early spring. To encourage new growth, do more spring pruning (resulting in summer flowers). Prune in summer after flowering, and prune sucker habits as required.