Shrubs are essential elements of a structured and attractive garden. Planting shrubs is an excellent way to beautify your outdoor space while enjoying relatively simple maintenance. This complete guide explains when and how to plant shrubs to ensure their growth and health. We will cover the following points: planting period, planting technique, watering, planting distance, and fertilization.
When to Plant Shrubs: Spring, Summer, or Fall?
The sale of container-grown shrubs offers great flexibility for planting. It's possible to plant shrubs in spring, summer, or fall. Here are the advantages and disadvantages of each season:
- Spring Planting (March to June): Ideal for vegetation recovery. Mild temperatures and frequent rains promote root establishment. This is the best time for summer-flowering shrubs like Spirea, Potentilla, Weigela, or certain types of Hydrangea (Hydrangea paniculata, arborescens).
- Summer Planting (June to August): Possible, but requires more frequent and abundant watering, especially during hot and dry weather. Avoid heatwave periods.
- Fall Planting (September to November): An excellent period for many shrubs, especially evergreen shrubs like **hedge cedars, pines, spruces, or junipers. The soil is still warm, allowing roots to establish well before winter. Conifers and acid-loving plants (for example, hardy rhododendrons adapted to your zone) appreciate fall planting.
How to Plant a Shrub in 5 Key Steps
Planting a containerized shrub is simple. Here are the steps to follow for successful planting:
- Dig a hole twice as wide as the pot and slightly deeper (5-10 cm). Loosen the bottom of the hole with a spading fork, especially in heavy soils.
- Mix the excavated soil with compost or planting mix like the Botanix Planting soil mix 3 in 1 and a handful of bone meal. For heavy soils, add drainage materials (perlite).
- Water the shrub's root ball thoroughly in its pot before removing it.
- Gently remove the shrub from its pot and lightly untangle the roots if they are root-bound. Place the shrub in the centre of the hole. The root collar (junction between stem and roots) should be at ground level. Orient the shrub to display its best side.
- Fill the hole with the soil mixture, tamp lightly, and form a watering basin. Water generously.
What Planting Distance to Respect Between Shrubs?
It is crucial to maintain sufficient planting distance between shrubs to avoid competition and diseases. Consult the plant tag or ask your nursery staff for advice. As a general rule, leave a space equivalent to the shrub's mature width between each plant. Good planting distance is essential for the health of your shrubs and the formation of dense hedges.
Watering Shrubs: Frequency and Tips
Regular watering is essential, especially during the first year after planting, while the root system establishes firmly.
- Spring: Water generously 1 to 2 times per week if rainfall is insufficient, especially during periods of renewed growth.
- Summer: Water 2 to 3 times per week, or more during intense heat and prolonged dry spells. The goal is to keep the soil moist but not waterlogged. Water preferably in the early morning or late afternoon to limit evaporation.
- Fall: Gradually reduce frequency. Water once a week, adjusting according to rainfall, until the ground freezes. A final generous watering before winter is beneficial, especially for evergreens.
Tip: Mulch the soil around the shrubs with a 5 to 10 cm layer of organic mulch (wood chips, bark, decomposed compost). This limits water evaporation, keeps the soil cool, reduces weed growth, and, as it decomposes, improves soil structure. Leave a small space without mulch directly at the base of the shrub to prevent collar rot.
Fertilizing Shrubs: When and What Fertilizer to Use?
Fertilization helps provide the necessary nutrients for vigorous growth and beautiful blooms.
- In Spring (May to June): Use a complete shrub fertilizer rich in nitrogen (N) to promote foliage and stem growth. A slow-release granular fertilizer (like the BOTANIX 15-5-15, or similar balanced fertilizer) is practical, or a handful of well-rotted compost lightly incorporated into the soil surface around the base (without touching the root collar). Follow the dosage instructions on the product packaging.
- In late Summer or early Fall (August-September): Apply a fertilizer rich in phosphorus (P) and potassium (K) and lower in nitrogen, such as a fall fertilizer (e.g., BOTANIX 4-8-16 or equivalent). This helps the shrub strengthen its roots and build up reserves to withstand winter, improving its cold hardiness.
Managing Diseases and Pests
Healthy and well-maintained shrubs are more resistant to diseases and pests. Regular monitoring allows for quick action if a problem arises.
Prevention:
- Choose resistant species and varieties: Some plants are naturally less prone to common diseases.
- Ensure good air circulation: Respect planting distances and prune if necessary to allow air to circulate through the canopy.
- Water at the base: Wetting the foliage, especially late in the day, can promote fungal diseases. Water directly at the soil level instead.
- Maintain cleanliness: Remove dead leaves or plant debris from under the shrub, as they can harbour disease spores or insect eggs.
Detection and Action: Regularly inspect your shrubs, observing the foliage, stems, and buds.
- Common symptoms: Spots on leaves, yellowing, deformation, presence of insects (aphids, mites, caterpillars...), webs, powdery deposits (powdery mildew).
- First steps: Often, a simple spray of water can dislodge small insects like aphids. Pruning affected parts (diseased branches, heavily infested leaves) is often an effective solution; dispose of these residues in the trash, not the compost.
- Gentle treatments: For more significant infestations, first try less toxic solutions like insecticidal soap if suitable for the problem. Always follow usage instructions.
Prompt action at the first signs of stress or infestation often resolves the issue before it worsens.
Successful planting is the first step towards a thriving and attractive garden. Remember that each shrub is unique. With a little care and attention, your shrubs will beautify your outdoor space for many years.