Sturdy like a bush, floriferous like an annual, that’s how one might summarise a perennial plant in two words. In theory. In practice, promises can sometimes be hard to keep: here are 4 misconceptions circulating about perennial plants that we propose to debunk...
Misconception No. 1: A perennial is like an annual; I plant it and in 3 months I have a bush overflowing with flowers
False.
Experience: plant a young plant of a perennial in spring, water it, and give it the necessary dose of fertiliser, and in 3 months you will have... the same plant, or almost. In any case, you won’t have the bush overflowing with flowers you were hoping for. Instead, despite your efforts, you will have a stump of leaves and, if all goes well, 2-3 flowers that will duel for attention. Add another dose of fertiliser and water daily to speed up growth, and you will end up with... a dead plant or one on the verge of dying.
In contrast to annuals that live for a year and die, perennial plants have a life cycle of three years or more; most can live 15, 30, or even 50 years without flinching. "Perennial" is a horticultural term that refers to a herbaceous plant that persists in its vegetative structure. A perennial plant is primarily a stump and roots. A stump that stores food and roots that explore the soil to provide the water and nutrients necessary for the plant's life.
Once out of its pot and planted in its new environment, the plant will seek to be self-sufficient to prepare for all eventualities; it will quickly explore its new surroundings and build its reserves. It will grow a lot, but underground, which leaves the gardener perplexed as they see it "struggling". If a perennial plant is overfed, pampered by fertilisers, and comfortably settled in a warm greenhouse, in a soft substrate and watered to its liking; the sudden return to the wild can be a shock, sometimes insurmountable, which encourages laziness and requires a lot of time to acclimatise.
Be aware that:
- The quality of a perennial plant at planting is assessed based on its roots and stump, not its foliage.
- A perennial plant is generally truly beautiful in the garden one to two years after planting.
Misconception No. 2: It’s better to buy perennials in large pots than in young plants
Generally false.
Experience: plant two perennials of the same variety side by side, one purchased in a pot, the other in a young plant; wait 3 months and observe... the plant from the pot will not have grown any more than the one from the young plant.
A plant in a 9 cm (0.6 L) pot does not grow any faster or slower than a perennial in a 2 or 3-litre pot. However, a potted plant will have a stronger immediate presence in the garden; the larger the pot, the more noticeable the plant will be in the garden.
The choice between pot and young plant only depends on your patience and the effect you want in the short term. Planting a grass in a pot (Miscanthus, Pennisetum) can be beneficial if you want a quick presence in the garden; however, planting ten hardy geraniums in pots is not very useful since the plant has a fairly rapid growth rate. It is better to opt for the young plant, which is much less expensive.
Misconception No. 3: A beautiful flowering plant establishes itself much better than a young plant at rest!
False.
Don’t let your intuition guide you, “The more it’s in bloom and developed, the better the establishment will be.” Resist the temptation to plant your plants in early summer when they are in full bloom, and because “to be honest, it’s much more pleasant to plant in the garden in nice weather.”
In spring, a young plant of a perennial is often "empty", filled with potting soil and roots, with no real signs of life, and in autumn it’s worse; the plant seems on the verge of dying, the leaves are spotted, sometimes yellow, in short, the plant seems about to give up. Yet, this is the best time to plant perennials. A cool soil, a still mild temperature without being hot, and a plant at rest, that’s the equation that allows for the best results for successful planting!
“What does a beautiful perennial look like then?”
A beautiful perennial is primarily a stump and roots. A thick stump, bearing well-swollen buds and often white roots that fill the pot and testify to a life outdoors.
It is therefore better to buy a plant at rest than in bloom, and even if the plant you are buying has flowers, cut them off at planting; this will stimulate rooting. Remember that planting a perennial is anticipating the years to come, unlike annuals that must be beautiful in the year, perennials have one obligation: to root! On this point, they are not all equal. While you may have to wait 1 year to see a nepeta or a hardy geranium covered in flowers, it may take 2 years to admire the first flowers on a herbaceous peony and even 3 years to see the curious flowers of a Baptisia.
A beautiful perennial is, in most cases, a beautiful stump and a beautiful root structure, with little or no vegetation, because you are planting at the right time: during the vegetative rest period, in autumn or early spring.
Misconception No. 4: A perennial is indestructible; after all, it’s perennial!
False.
Often, the beginner gardener does not take into account the cultural guidelines provided and plants where THEY decide. Following one’s instinct and desires (“The large pink Astilbe would be really beautiful near the terrace in the sun”) is simply playing Russian roulette (and risking watching your astilbe "die of heat" all summer).
Succumbing to the charm of perennials can sometimes be costly, says the beginner gardener who is seduced by a beautiful specimen and forgets to ask THE question, "What are its requirements?"
Perennial does not necessarily mean hardy and certainly not "for all soils". A perennial plant has its requirements, although it is true that planting a perennial in the sun in fresh, rich soil suits many of them.
There are nearly indestructible perennials that thrive in all conditions, such as hardy geraniums, phloxes, asters, or epimediums, but most require reasonably specific growing conditions to thrive. And some are reserved for very experienced gardeners. A novice gardener planting difficult varieties is like a skier who has just earned their first star and decides to tackle a black run...
To avoid seeing your perennials die, ask yourself, before each purchase or planting, the 3 basic questions:
"Does it like the sun?"
"What type of soil does it prefer?"
"Does it require a lot of water?"
Once you have found an answer to each of these 3 questions, you will know if this variety is for you, and also where to plant it in the garden!
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