How to plant perennials

← Advice & Tricks of the trade

Perennial plants are wonderful for bringing colour and interest into our gardens and containers throughout the seasons. They also provide pollen and nectar which a diverse range of pollinating insects find irresistible.

Spring and autumn are the best times to plant perennials. By perennials we mean a plant that dies back in the winter but returns the following spring however, some perennials are evergreen and the following basic ‘rules’ still apply.

When planted in spring, the soil will be reliably moist and as temperatures continue to warm, this helps plants to establish well. When planted in autumn, the soil is already warm so they can get established before winter sets in and the autumn rain should keep the soil moist. Having established a new root system in autumn they usually romp away in spring. 

What should I do?

 1) Clear the area of weeds, taking care to remove the roots of any perennial weeds, and dig/make a hole just slightly larger than the pot the plant is in or if you’ve divided established perennials the resultant clump of plants.

2) Set the plant in the hole at the same depth it was growing previously. If it’s completely dormant and has no top growth, mark its location with a small stake or label. That way you’ll know where it is when weeding. The same is true if you’re planting bulbs.

3) Backfill with soil around the roots, firming it in with your fingers. Even with small plants, it pays to backfill and firm in a couple of times to eliminate air pockets, as these can cause root death. Water in thoroughly and top up with more soil if it settles. When planting several perennials, check how wide they’ll grow, so they don’t end up overcrowded or flopping onto a nearby path or lawn.

4) It’s important to keep newly planted areas moist while the plants establish so you’ll need to monitor the weather and water in dry periods  

5) The above steps also apply to planting in containers but make sure drainage holes in the bottom are clear and unobstructed before adding compost/soil. 

6) In our experience, when planting containers with perennial plants we use a potting mixture of 2 parts multi-purpose compost to 1 part soil-based compost e.g. John Innes no. 3. We’ve found that adding the soil-based compost adds some oomph to the mixture. It adds weight, provides extra nutrition and it’s ‘re-wetting’ capability is often much better than multi-purpose compost which is essential if the compost dries out. Try to avoid using a soil-based compost on its own as it can become very ‘claggy’ and compacted especially in the winter. The multi-purpose compost opens the structure of the planting mix which allows easy root penetration.

7) Planting bulbs with perennials works well, as the perennials will conceal the dying bulb foliage. Remember to allow bulb foliage to die back naturally and don’t be tempted to cut it off once the flowers are over. The bulb need to re-absorb nutrients from the foliage which will promote good bulb growth for the following year.

 

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