Perennials

Perennial plants give you a large selection of colour options and you can look forward to their return every year.

Annuals

an excellent way to ensure colour in your yard all summer long.

Any plant that grows, flowers, produces seeds and dies over the course of one year is considered an annual.

Perennials have many uses in the garden, and since most of our perennials are offspring of our native wildflowers they are quite hardy here. There are perennials for almost every garden situation. Introduce some hardy beauty to your yard or beds.

Perennials are non-woody plants that live longer than two years. They generally bloom once a year, for anywhere from a day to more than a month. Most perennials die back to their roots in the fall, although some varieties will remain green throughout the winter. Some perennials, such as hollyhock and delphinium have a short lifespan, and may live for only four or five years. Other perennial plants such as aster and peony can last for decades with little attention. Perennial plants give you a large selection of colour options and you can look forward to their return every year. They are also considerably easier to move than most shrubs. Do not expect your perennials to flower the first year you plant them. It usually takes these plants a full season to become well established and they will flower the second year.

With the crazy weather patterns we have experienced over the past couple of years, plants that can withstand our ever-changing climate are very appealing. Perennials such as hosta and bleeding hearts (Dicentra) are excellent in the shade while salvias and sedums enjoy the sun. We will have new varieties available to expand your collection as well. Come into the perennial area and you'll find a unique display of shade tolerant plants to give you some great options for those shady spots. We will have additional perennial displays where you can see sun loving plants, low growers and plants that are in bloom.

Try planting smaller varieties in clusters, but larger perennials should be planted on their own. Once perennials are established, they need very little maintenance. Remove debris from the area in the spring, water when needed, and fertilize in spring and early summer. In the fall, tall plants can be cut down to 18-24 Inches (45-60 cm) or left throughout the winter. They will trap dry leaves and snow, which helps to insulate the roots over the winter.

greengate Garden Centres is pleased to offer Heritage Perennials. Look for distinct blue pots by Valleybrook Gardens, a Canadian family-owned nursery. One of North America's largest wholesale producers of herbaceous perennials, Valleybrook Gardens grow millions of plants annually at two facilities: Abbotsford, British Columbia and Niagara-on-the-Lake, Ontario.

Perennials are a hardy and attractive addition to any yard. They require little work, and come back every year bigger and better. Consult our knowledgeable greengate Garden Centres staff for recommendations and helpful advice.

Perennial vines will come back again season after season, unlike tender annual vines. These hardy vines flower on old or new wood and provide excellent privacy or decoration when grown up a trellis or a wall.

Dividing Perennials

If the flower quality and quantity drop in your mature perennials this may be a sign of overcrowding and they may need dividing. Some simply outgrow the place they are in; other plants, as they grow, can create too much shade for sun loving perennials. Many perennials form clumps of stems. These stems are actually individual plants with their own root systems. Some perennials cannot be divided if they grow from one central stalk. Early blooming perennials should be divided in early fall. When all the leaves have fallen, gently dig up the plant and separate the roots of the individual clumps to be removed. Replant the removed plants in an appropriate place in the garden. Later flowering perennials should be divided in the same way in the spring, as soon as they are showing growth.

Perennial Maintenance

Routine feeding and watering will generally be enough to satisfy the nutritional needs of perennial plants through their growing season. Remove spent flowers on perennial plants or deadhead to encourage flower production. Prune back and mulch for extra protection in the fall. Remove this mulch in the spring. If you do not wish to mulch, leave foliage on plants, as leaves will collect snow for insulation and moisture during the winter. Prune away the dead foliage in the spring.

Clematis

These hardy perennial vines are known for their profusion of colourful flowers. Due to the differences in pruning requirements for various clematis they are classified into three major pruning groups for maintenance.

Group A or 1 – These clematis flower only on the previous year's growth. When blooming is finished in June, prune off dead or weak stems.

Group B or 2 – These clematis bloom on previous year's growth, often in early summer and again in late summer. Unfortunately, they are not hardy enough here for the summer's growth to survive the winter - they die back to almost ground level, so they rarely bloom here. They are a challenge.

Group C or 3 – These clematis flower only on the current years growth. They are the most commonly grown, as they flower most of the summer, with little care.

Clematis need varying amounts of sun for healthy growth. Some need full sun, while others can tolerate almost total shade. Read labels or ask questions before making a choice.

Note: Clematis should be planted approximately six inches deeper than they are in the pot.

Perennial Pre-planting

Garden and bed soil preparation

Ideally, soil preparation for the planting of perennial plants will be done in the fall. If this is not possible, however, organic material, such as compost or manure, should be worked into the soil in the spring. This will help the soil retain moisture, improve drainage, add oxygen and improve root growth.

Gypsum can be added to heavy clay soil to make it easier to dig in organic material.

Fall Soil Preparation

  • Remove all garden debris from planting site, add to composter for future use.
  • Spread layer of organic material several inches thick over area. Compost or manure is ideal for this.
  • Turn organic material into existing soil using gardening fork.
  • Note: Large lumps should be left in the soil at this point. Frost helps to break soil into a less dense soil structure, ideal for plant growth and moisture retention.

  • Turn again in the spring, shortly before planting. Break down large lumps of soil with a garden fork.

Note: Slow release fertilizer can be turned into the garden at this point, if desired.

Spring Soil Preparation

  • Remove all garden debris from planting site a few weeks before planting.
  • Turn existing soil using gardening fork, breaking up lumps.
  • Add 4-6" of organic material and turn over again.

Note: Gypsum can be added to heavy clay soil to make it easier to dig in organic material.

Planting Perennials

Perennials can be planted anytime from spring to fall. If the ground can be worked you can plant.

Your choice of perennial will depend on two main things, the size of the area that you wish to fill, and the reason you are filling that spot. When considering a plant for a certain area, be sure to consider the plant's ultimate size. Be sure not to plant too close to houses, garages, or other permanent structures.

Plant perennials anytime from spring to fall. If the ground can be worked, you can plant.

  • Dig a hole 1.5 times the width of the root-ball or the pot that the plant comes in and a little deeper.
  • Remove the plant from its pot or remove burlap if bare root and gently massage roots.
  • Plant the perennial in the hole at the same level it was planted in the pot.
  • Fill in hole with a mixture of topsoil and compost.
  • Water plant in well and fertilize with a transplant fertilizer (10-52-10) or myke.

Note: Peat pots should be removed from all plants planted in the Calgary area, as they do not degrade quickly in our short growing season.

Perennial Plant Care

Perennial plant maintenance

Routine feeding and watering will generally be enough to satisfy the nutritional needs of perennial plants through their growing season. Spent flowers on perennial plants should be removed, or deadheaded, to encourage flower production. Perennials may be pruned back and mulched for extra protection in the fall. This mulch should be removed in the spring. If you do not wish to mulch, leave foliage on plants, as leaves will collect snow for insulation and moisture during the winter. Dead foliage should be pruned away in the spring.

Spent flowers on perennial plants should be removed, or deadheaded, to encourage flower production.


Dividing Perennial plants

If the flower quality and quantity drops in your mature perennials, this may be a sign of overcrowding and they may need dividing. Some may simply have outgrown the place they are in or other plants, as they grow, may be creating too much shade for sun loving perennials. Many perennials form clumps of stems. These stems are actually individual plants with their own root systems. Some perennials cannot be divided if they grow from one central stalk. Early blooming perennials should be divided in early fall. When all the leaves have fallen, gently dig up the plant and separate the roots of the individual clumps to be removed. Replant the removed plants in an appropriate place in the garden. Later flowering perennials should be divided in the same way in the spring, as soon as they are showing growth.

One of the greatest things about plants is their innate ability to recover from damage and that's why it's perfectly ok to divide your perennials. In fact, most perennials benefit from being divided. Doing so can keep them healthy, vibrant, and contained in their place at the same time providing you with good quality plants for other places in your garden. Late summer is the perfect time to do it as the temperatures are a bit cooler. Try to avoid dividing perennials during the heat of the day; early morning or evening is ideal.

There are many reasons to divide your perennials; more plants are just one of the reasons. Some perennials grow very quickly forming large clumps. These clumps can begin to die through the centers every few years or so. This leaves bare spots in the middle and the plant itself looking lackluster and tired. As your perennials grow over the seasons, they also tend to grow into each other creating competition that just didn't exist when you planted them. This tends to lead to smaller plants and flowers. This goes especially for vigorous growing plants like the Obedient plant which can overwhelm their neighbours in just a couple of seasons. Dividing your perennials circumvents these issues and leaves you with perfectly good plants to use elsewhere in your garden or share with friends and family.

Dividing your perennials is a rather simple process and it ensures your perennials will grow better in the years to come. First, determine which perennials you are going to divide. Plants that are not fully flourishing, are bare in the center, produce fewer flowers, or are crowding borders or other plants are good candidates. Water these plants thoroughly a day or two in advance of the dividing process as it will help by softening the soil so when you divide its easier on you and the plant itself. Here are all of the ins and outs of dividing your perennials so they last for years to come.

Use a garden fork or shovel to dig down on the outside of the root-ball and lever the plant loose from the soil. Once the plant has been loosened, try to center the root ball on the tool and gently lift the plant from the soil. You especially want to take care that you lift as much as of the root as possible without tearing up the root system. Try to leave it in a ball. Once the plant has been uprooted gingerly, shake the excess dirt from the roots and wash them clean with water. This will make it easier for you to divide the clump.

You will see the plant has individual crowns that form the clump. Divide the plants at the crowns by cutting or hand prying them apart. Each crown will need to have roots and leaves in order to survive the process. The amount that you divide the plant is up to you and the space requirements you have, but try not to divide it into too many small pieces. Promptly replant the divisions before there is any chance that the roots may dry out. You may want to have some areas ready to plant ahead of time. Plant the divisions at the same depth as they were when you dug up the perennial. At this point, you could also fertilize with bone meal, or give it the best chance possible with a mycorrhizae beneficial fungus like Myke, then water it well. If it's super dry, then you should also cover the freshly planted root area with mulch to retain moisture until your plants establish themselves. If you are saving plants for friends, move the plants to a shady area and keep the roots moist with a damp cloth or paper towel until you make the hand-off.

Perennials such as Bearded Iris grow from rhizomes which are much like bulbs. You can tell a rhizome by a fleshy stem that grows along the ground. The very best time to divide rhizomes is late summer as these plants rest during this period. Carefully dig out the rhizomes with a shovel or trowel and then wash off the excess soil to expose the shoots. Each viable rhizome will have roots growing out the bottom and a set of fan leaves at the base of the shoot. Cutting the foliage back by 2/3 will help prevent moisture loss and focus more of the plant's energy on root development. If your rhizomes have grown together very closely or if your plants have become very mature, you can also divide the rhizome. Split them by breaking or cutting them. Replant them in a sunny spot with excellent drainage and as before, use bone meal at the bottom of the hole, or use Myke directly on the roots, and water them well. You may also want to treat your rhizomes with a fungicide to stop mould or other diseases.

While most perennials benefit from being divided every few years, there are a few that don't.

Avoid dividing these varieties:
  • Balloon flowers (Platycodon)
  • Baptisia
  • Bleeding heart (Dicentra)
  • Butterfly weed (Asclepias)
  • Christmas rose (Helleborus)
  • Cushion spurge (Euphorbia polychrome)
  • Gas plant (Dictamnus)
  • Lavender (Lavandula)
  • Oriental poppy (Papaver orientale)


If you are in doubt, these perennial varieties should be divided every 3-4 years:
  • Astilbe
  • Bee balm (Monarda)
  • Black-eyed Susan (Rudbeckia)
  • Daylily (Hemerocallis)
  • Hosta
  • Peony (Paeonia)
  • Phlox
  • Purple coneflower (Echinacea)
  • Siberian iris (Iris sibirica)

If you're not sure if you should divide your perennials, just stop in at greengate. We will help you identify whether or not a plant can be divided. So, get out there and make some new beds for your beloved perennials and they will live on happily ever after. Happy gardening!