How To Plant Perennials: An Expert Guide

How To Plant Perennials: An Expert Guide

How To Buy & Plant Herbaceous Perennials

There are a number of ways that you can buy and plant perennials, especially at the beginning of the season. Small pots are on sale in volume on the internet, in garden centres and DIY and Home Depot stores.


Bare root perennials are offered in shops in colourful packets and on line. Larger pots of certain varieties appear early and the range increases as the season progresses.


Gardening experts and design gurus will often recommend planting in groups of three, five or seven of one variety, or even in bold drifts.


That's all very well, but if the individual price ticket is high, or you only have a small space to work with, is that realistic?



Perennials in small pots


Plant ‘plugs’ are available online if you are buying in bulk, but will need potting + growing on undercover before being planted outside.


Plant ‘plugs’ are available online if you are buying in bulk, but will need potting + growing on undercover before being planted outside.


Widely available at the beginning of the planting season, small pot perennials, in other words those grown in liner pots, (sometimes called P9’s 3.5” or quart pots)  offer the most economic way to buy herbaceous plants, P9 European pot size


The P9 or 9cm European pot size is the most economic way to buy herbaceous perennials


They are an inexpensive way of planting and generally offer the best value as they make it realistic to plant in a group of three, even in a small space.


US pots are measured in Gallons


American pots are measured in gallons and European pots in litres


This results in more impact, more quickly from vigorous young plants that will not need dividing for at least two or three years. Subjects offered in this way tend to be more mainstream and easy to produce. Expect lots of seed raised varieties.


Be sure to order early as come mid spring, nurseries often-pot up liner plants into large pots to sell at a higher price.


Today lots of seasonal bedding growers are producing “perennial” varieties. Look out for Lucanthemum, Agastache, Echinacea and Rudbeckia sold in this way.



Bare root perennials


bare root perennials
Perennials offered bare root (often sold in plastic bags contain a little dry compost) are those with thick, often fleshy roots. . They are not as resistant to desiccation as bulbs and corms, so need to be bought very early in the season and  planted without too much delay.


If they are a good size and from a reliable source this can be an economical way to acquire plants of varieties that are much more expensive pot grown.


Those offered in prepacks in garden centres and other retail outlets rely on a colour picture to sell the dream.


Those offered mail order and online are sold on picture, description and promise. Only buy from trusted reliable sources and don't buy stock that seems too cheap.


Results can be disappointing. Agapanthus are often sold in this way, although they are often those that favour warmer growing conditions. Surprisingly small pieces of bearded iris rhizome sold in packets do surprisingly well.



Large pot perennials


4 Iris 'Plum Tart'
Perennials offered in large pots at a higher price may produce bigger plants and more impact in their first year.


If stock has been over wintered, make sure it is starting to grow and is alive. Some varieties do not survive the winter in pots and you may be buying a pot of compost.


Also make sure you are not just buying a small pot perennial in a larger pot of growing medium. Again buy from a reliable source.


I would buy peonies in large pots, also hostas and oriental poppies. These are subjects I will use individually and I don’t want to wait a couple of seasons for them to grow.


5 Large pot perennials


So, coming back to the matter of planting in singles or multiples.…….



Which is the best way to plant perennials?


If you have a small garden or bed to plant and want variety then you will probably plant single plants of individual varieties. What does help, if you have the room, is to plant multiples of one variety to bond a planting scheme together.


This could be something like nepeta, or a perennial geranium that you repeat near the edge of the bed to unify a planting scheme.


Alternatively it could be a light, upright growing subject that you drift through the rest of the planting. For example Digitalis lutea. This delicate little foxglove is truly perennial and is ideal to add light height in amongst other perennials, roses and shrubs.


Digitalis lutea


If you have a large space then planting in drifts has massive impact. It also means your planting is more easily identified by bees, butterflies and pollinating insects.


In this case I would opt for multiples of varieties with small flowers and spikes, punctuated by some individual specimens of those with “bold blooms”, for example peonies and poppies.



Perennials from seed


7 Bold drifts of knatia and geranium


Some perennials, and plants grown as perennial are worth growing from seed. It is worth remembering that successful propagation from seed usually results in a large number of offspring.


8 Digitalis purpurea var. albiflora


If you only want one red oriental poppy, buy a plant. If you want twenty or more then seed is an option.


Biennial subjects that are perennial in your garden by seeding themselves such as honesty (lunaria) and foxgloves (digitalis) are definitely worth growing from seed. If this does not appeal buy them as small plants in pots.


9 Perennial border


Although fall is regarded as the time to plant trees and shrubs, perennials are usually best planted in early spring.


That way they avoid the cold and wet of winter and put on new growth quickly. Most perennials are clump forming and the active, vigorous part of the plant is around the edge of the clump. That’s why we lift and divide every few years.


Planting on the brink of the growing season gives them the best possible start in life.



Further Study


Naturalistic Perennial Meadow Planting Design a 4 week online gardening course with international author and planting guru Michael King

Noel Kingsbury: Planting Design with Perennials a 4 week online gardening course with international author and plantsman Noel Kingsbury

Planting Design with Grasses A 4 week online gardening course with international author and planting guru Michael King

Get free gardening hints and tips

We know that getting too many e-mails can be annoying so we'll only send you gardening tips from our expert tutors and won’t pass your details onto anyone else.