Perennial plants consist of a huge variety of species, from tall perennials like Agapanthus 'Brilliant Blue' to colourful perennials like this gorgeous 'Georgia Peach' Heuchera and container-grown perennials like Senecio Angel Wings. Once established, by planting bulbs in containers or planted straight into flowerbeds, these perennials thrive with minimal help.
Besides trimming away dying bulb foliage, adding more soil and fertilise to potted plants, and deadheading flowers, there's little that you need to do. The trick, of course, is knowing when and how to plant herbaceous perennials in the first place.
This guide will cover everything you need to know about when the best time to plant your perennials is, whether you have bulbs, seeds, flowers, or bare root varieties.
If you are a customer at Gardeners Dream, you can click on any product to learn more about how it likes to be planted and cared for!
Quick answer: when to start planting perennials
The trick when planting perennials, including bare-root perennials, is to get them established and ready for the growing season. So, the best time for most plants is spring or autumn. Which season you choose often depends on the flowering season. For example, autumn planting is best for plants that bloom in spring. Meanwhile, summer and autumn flowering plants are best planted in spring. Non-flowering plants give you more flexibility.
So, what happens if you plant outside of those seasons in the winter months? Well, most plants will not survive easily. Young plants need a moist soil mixture which spring and autumn rain provides, but hot summer suns and winter frosts are the enemy. Harsh weather, both hot and cold, can kill the root ball. So, don't plant beyond the end of autumn and try not to extend too far from early spring.
Pot-grown perennials allow for a little more flexibility, as the perennial's container protects it from the elements and can be moved around to find a sheltered spot. With some well-rotted manure for fertiliser, you could plant potted perennials in the summer - but try to wait until spring or autumn if you can!
Herbaceous perennials and other types
There are many different perennial plants to choose from, so horticulturalists are dividing perennials into smaller groups based on their characteristics. Here are a few terms you should be familiar with:
- Herbaceous - this means that the plant is flexible with green stems rather than woody stems. Most perennials are herbaceous!
- Pot-grown perennials - this is self-explanatory, meaning plants that grow well in pots. These perennials will die back and regrow as well-established plants each year but from a container.
- Perennial weeds - weeds that come back year after year. You can mulch to suppress weeds, but the best way to remove them is to find your trowel and get to work.
- Bare root - this plant quite literally has bare roots. Grown in nurseries, these perennials are dug up when they are dormant so they can be stored and transported. These plants need to be planted during the dormant season, from autumn to the start of spring. At Gardeners Dream, we prefer potted plants.
- Hardy - as the word suggests, hardy plants are tough cookies. These plants can survive well in unfavourable conditions, whether it's soil that can't retain moisture or extreme weather conditions. Although they aren't invincible, hardy plants are difficult to kill and usually don't need any special attention.
- Evergreen/deciduous - perennials can be evergreen, meaning they retain attractive foliage all year round, or deciduous which means they drop their leaves in the winter and change with the seasons.
Regardless of the type of perennial you choose, the planting method is pretty much the same. Plant in the spring and autumn to keep the soil moist, prune as necessary, remove dead seed heads, and fertilise yearly with well-rotted organic matter or liquid fertiliser.
How to plant perennials
You can find hundreds of types of perennials, especially when you are ordering online. Regardless of whether you order the eye-catching Lupinus Beefeater or are enamoured with your Geranium Dark Eyes, the method for planting them is very similar and relatively simple too. Here's roughly what you need to do:
- When your plants have been delivered and it is the right time of year, it's time to start. Wait for dry weather between rain spells, so the garden soil is moist but not waterlogged.
- If your soil is infertile, mix in some potting mix or a well-rotted garden compost before planting.
- Next, dig a hole using a garden fork and trowel. You should also remove any weeds in the surrounding soil and check for roots left behind by plants growing previously in this spot.
- The hole should be the same depth or slightly deeper than the length of the roots, so the stem part of the plant is above the soil surface.
- Once in the hole, add soil around the roots and pack down firmly to eliminate air pockets. You should also water the perennial plant, even if rain is forecast and the soil is moist. This even goes for plants that typically don't like too much water. This is because heavy watering right after planting will help the soil compact down further and allow those roots to establish well.
- Finally, you can stake with a bamboo cane, cover for frost protection, or follow any other care requirements outlined for the plant. For example, Nepeta Cats Pajamas should be cut back before the first flowering once planted out in your garden. If you are ordering from Gardeners Dream, you will find care instructions on our website - just click on any plant to get started.
That's really all there is to it! The charm of perennial plants is that they come back year after year, so once you have established your perennial, you can sit back and enjoy the foliage and flowers.
FAQs
Can you plant perennials all year round?
Perennial plants are best planted in spring or autumn when the warm soil (or at least, not frozen solid soil) is perfect for digging and the weather is moderate. With garden compost and planting at the same depth as any other plant, perennial plants establish well with minimal effort, so long as they are planted in spring or autumn.
What is the easiest perennial to grow?
There are so many perennials to select, but if you want one that is easy to grow and maintain, look for a hardy perennial. Examples include creeping phlox, which provides good ground cover, and echinacea or cone flowers for vivid colours and bee-friendly blooms. Although perennial varieties need to be planted at the right time, there's very little that you need to do to maintain hardy varieties besides fertilising with some well-rotted manure once a year.
What month is the best time to plant flowers?
Spring and autumn are the best time, as moderately warm soil is easy to dig and mix with compost for soil fertility. During these seasons, the weather isn't too harsh, so the few roots that new plants have can be established easily before the flowering season. Most flowers need to be planted the season before they flower, so if they are spring flowering bulbs then you should plant them in the autumn, allowing roots to establish and growth buds to flourish. Keep in mind that you will need to deter weeds as your flowers begin to grow, so they aren't competing for nutrients!
Where is the best place to plant perennials?
Perennials are best planted in beds and borders, though some smaller plants may also be suitable for container planting. The roots spread, so make sure any perennial is planted with enough space for the root system. You should also fertilise with well-rotted manure, especially for new beds and borders.
What month is best to plant perennials?
It is best to plant perennials in the spring or autumn. Although it may seem a good idea to plant in the winter months, with soil visible for easy planting, the cold weather can damage the fleshy roots and frosts could kill off top growth. Instead, wait until spring or autumn when the ground is still moist but the weather isn't too harsh.
Can you plant perennials in winter in the UK?
Planting your perennials in winter in the UK is not advisable. Even with two garden forks, trying to dig a hole in frozen ground is hard work. Furthermore, the frosts could lead to root death even if you manage to get the plant established in the ground. To avoid the cold frame that is winter, plant in the spring or autumn.
What is the latest time to plant perennials?
Late autumn, towards the end of October, is the cut-off for planting perennials. The further you get into winter, the more soil is frozen and has fewer air pockets for plants to thrive with, and the harsher the weather is. If autumn has passed, it is best to wait for spring when the weather and soil are more suitable for planting.
