Perennial plants and flowers make a garden look better and better with age. Perennials are ornamental plants that do not die after one season of growth. Many perennials are considered to be short-lived as they last only 2-3 years. Rose Campion is a short lived perennial, but because it self-seeds so readily, it appears to live much longer.
Not all plants with the ability to be perennial are hardy in all areas. This is why planting zones are so important. Knowing what zone you garden in will allow you to determine what plants will survive in your area.
Blooms: Mid-summer to Autumn
Colours: Purples or white
Although native to marshy areas, Liatris is surprisingly drought tolerant and accepting of all types of soil. It is a tireless bloomer and the spiky flowers and grassy foliage add definite textural interest to the garden. To avoid staking, select a compact or low growing variety.
Colours: Purple, white, orange, yellow, pink and red. This rugged prairie plant can be found in almost any colour, including some bold, electric colours. The originals are still the hardiest, but as they keep refining the breeding of the newer varieties, they get better and better. Coneflowers will bloom all summer, with deadheading. Other than deadheading though, coneflowers almost take care of themselves.
Blooms: Late spring / Early summer, but grown for its foliage.
Colours: White, pink or red
Heuchera got its common name of Coral Bells because the original garden plant had dainty coral bell-shaped flowers.
The foliage was nice, but it was the froth of flowers that was the main attraction.
These days Coral Bells are more often grown for the colourful and variegated leaves. Heuchera come in shades of purple, butterscotch, mottled green and strips. Most varieties favour partial shade, where their season-long colour is always welcome.
Blooms: Late spring / Early summer
Colours: White or pink
Tiarella cordifolia spreads rapidly, but accommodates other plants by going around them.
It makes an ideal ground cover, giving four seasons of interest where the leaves are still visible above snow cover.
Fuzzy spikes of flowers shoot out above the maple shaped leaves. The velvety leaves remain attractive all season. Foam Flower will take care of itself if planted in a shady or woodland setting.
Blooms: Early summer to Early Autumn
Colours: Blue or white
Here is one thistle that is not weedy or invasive. Echinops don’t require dividing, because with its long tap root, it doesn’t like to be disturbed. It appears to bloom forever, because the seed head is as attractive as the bloom, so there is no need to deadhead.
Echinops even does well in poor, dry soil.
Blooms: Generally mid-Summer
Colours: Purples or white
Hostas are extremely low care perennials.
If slugs didn’t love them so much, they’d be almost perfect.
They do most of their growing early in the season and the thicker leaved varieties are less attractive to slugs.
Most do best in partial shade, but the golden leaf varieties can handle a good deal of sun.
Blooms: Late spring / Early summer
Colours: Pinks, white, reds or yellow
This favourite old-fashioned perennial looks does best if left alone. The heavy double blossoms may need some staking, if they don’t have other plants to lean on, but the single flowered varieties are usually able to stand tall on their own. The bushy foliage looks attractive all season. Peonies prefer to stay put and don’t adjust quickly to being divided.
From the day your garden is planted, it will need maintenance to keep your flowers blooming and looking good all summer long. Most flowers benefit from having their spent flowers removed. This is called deadheading. Flowers that repeat bloom will often do so only if the old, dying flowers are removed. If they remain on the plant, they will go to seed and stop producing flowers.
Many flowers that bloom only once in a season will benefit from deadheading. This is because the plant puts its energy into strengthening itself instead of producing seed.
Some exceptions to this rule are plants like Astilbe or ornamental grasses that bloom only once, but continue to look attractive with their drying seed heads.
Staking in spring means you will have a few weeks of visible, sometimes ugly stakes in the border, but it will prevent problems throughout the rest of the growing season.
What to Stake With?
Start with natural looking materials. Branches and bamboo fit in with garden plants better than metal and wooden stakes. However, there are places where metal rings make life easier and sometimes the strength of a square wooden stake is necessary. Using biodegradable tying material, like twine, will not only blend in more naturally with the garden, it will make fall cleanup easier, since twine can go right into the compost.
What Plants to Stake
- Tall Plants
Some exceptionally tall flowers, like hollyhocks and delphiniums, need staking. They will look fine one day and then wind or rain will level the whole lot of them. Once down, they won’t pop back up. In many cases, fallen stems will begin to bend up from where they hit the ground, growing in a kind of ‘S’ shape.
Tall, straight perennials can be secured to a thin bamboo stake placed close to the stem. Put the stakes in early in the spring so that you are not damaging roots later in the growing season. Tie the plant loosely to the stake by twisting the twine into a figure eight, so that the stem is not pulled tight up against the stake. Plants with large flowers, that tend to be top heavy, will need to be tied to the stake all the way up to the flower.
- Floppy Plants
Flowers like daises, asters and coneflowers might flop over on other plants, but you might enjoy the informality of a more natural garden. You can control the height of these plants by pinching or cutting back the plants earlier in the season. This encourages them to grow bushy and substantial and less tall.
You can support a clump growing plant, like coreopsis or asters, by circling the clump with bamboo stakes and wrapping twine around the perimeter of the stakes, forming a kind of cage. This will support the entire bottom growth of stems, while allowing the clump to retain a natural shape on top.
- Staking Plants that Split
Some plants simply need a little side support, like peonies. Peony rings are sold in most all garden centers. They are either an open ring or a ring with a wide spaced grid and three or four legs. Place these about 4-6 inches above the plant as it emerges in the spring. You can slowly raise the legs a bit as the plants begin to grow through the ring. Don’t disturb the rings once flowers buds have set.
How to Stake
Twiggy, fanned out branches from your tree or shrub pruning can be used as natural supports for border plants. These branches are often referred to as pea staking or trellis, because they have been used for years to support pea plants. Stick the branch close by the perennial in the spring and eventually the flowering plant will grow through and cover the twiggy branch. Choose a twiggy branch that is about 6-8 inches shorter than the mature height of your perennial.
Staking makes the garden look better throughout the season. It also makes maintenance easier, because you will not have to lift and move dropping plants off one another. You will probably discover plants you wished you had staked, as the season matures. Make notes for next year.
Many perennial plants grow in an ever widening clump. After several seasons of growing, these perennial plants will begin to die out in the center and look more like a ring than a clump.
To keep the plants vigorous and blooming, a technique known as ‘Division’ is performed. Dividing perennial plants gives you healthier, longer lived plants and the bonus of more plants.
When to divide perennials depends on the type of plant and how quickly it’s growing. You don’t have to wait until your perennial plants begin looking like doughnuts. In fact, it’s better if you don’t. Keep an eye out for clumps that have grown 2-3 times their size within 2-5 years. Any over grown clump or any clump that has simply exceeded the space allotted is a candidate for division.
Spring is usually the best time for division, since the plants are actively growing their leaves are not so developed that the root system can’t take a little disturbance and still feed the top of the plant. However, just as different plants can go different lengths of time before being divided, some plants, like peonies, prefer to be divided in the early autumn.
It’s true that dividing perennials is good for them in the long run. However it is still a shock to their system and giving them a good soaking, preferably the day before you intend to divide, will help your success.
Disturbing the root system of any plant interrupts its ability to feed and hydrate itself. Ensuring that the roots are well saturated before disturbing them reduces the trauma.
If you find you must divide a plant with a great deal of top growth, cutting back the leaves by about 1/3 will lessen the amount of work the roots will need to do to maintain the foliage. This is often the case when dividing bearded iris, after they have bloomed.
Along the same lines as watering your perennial plant well before digging and dividing it, having the new planting hole prepared before you dig will limit the plant’s time out of the ground and the stress on the root system.
Give your new division plenty of room to expand. Remember the divisions will all be smaller and will require less deep holes than the original plant.
In most cases, it is easiest to divide a perennial plant by first digging and lifting the entire plant. If that is the case, use a shovel or flat edged spade and slice completely around the outer perimeter of the plant, a few inches away from the foliage. Slice down several inches deep, at least 6 inches for most plants and more for extremely large, well-rooted plants. The idea is to dig as much of the root ball as possible.
Try and keep the soil intact around the root ball. This is an additional advantage of watering the soil around the plant. Wet soil adheres better than dry soil.
Once you have sliced completely around the plant, you will see the plant beginning to lift out of the hole. Try lifting the plant out of the hole with the shovel. It may be too heavy to lift this way. If so, use the shovel as a lever and lift the plant manually. Place it on level ground nearby.
A very common method of dividing perennials is to use 2 pitch forks to prise and split the plant apart. Perennial plants with fleshy roots, such as the daylily shown here, are easily prized apart with forks.
Insert the forks into the center of the lifted plant so that the backs of the forks are touching each other and the tines are crossing.
Press down so that the forks go through the plant. You will probably hear some cracking at this point. Let’s hope it’s your plant and not the handle on your pitch fork. In all seriousness, some plants are so dense that this method will not work. Exercise caution, since garden tool handles can break and send you tumbling.
Once your pitch forks are securely anchored in the center of your perennial, simply pull the handles in opposite directions, away from the center of the plant. Again, you will hear cracking. The roots will not be breaking cleanly, but the plant will recover.
Sometimes a densely rooted plant will resist and it will take two people to pull the forks apart and split the plant. And as mentioned in before, exercise caution, since garden tool handles can break and send you tumbling.
Keep pulling on the handles until the plant has completely split into two plants. If the resulting plants are a good size for replanting, meaning not so large you’ll have to divide again next year or so large that they don’t fit into the space you’ve allocated, you are done dividing and ready to replant.
If you have an extremely large plant, you may have to divide it several times before you have new plants of an appropriate size. Simply repeat the steps above.
However your divide your perennial plants, you should treat them like new seedlings.
- Try and do your dividing on an overcast day or at least not in during the hottest part of the day.
- Don’t leave the exposed root ball sitting about any longer than necessary. Hot sun and breezes will quickly dry the roots.
- Keep them well watered until new growth appears.
- Provide some shade if they appear to be wilting during the afternoon. A floating row cover will protect them from the hot sun.
Perennial plant division is intimidating when you first think about tearing apart your precious plants, but the more you do it, the better you will get at it and the better your perennial plants will grow.