Plant once - enjoy year after year
Perennials offer a world of elaborate visual interest. Many perennials are grown for their foliage rather than flowers and offer dramatic and interesting ways to landscape your outdoor living room!
Perennial means enduring. Unlike annuals that live and die in one season, any plant that endures the winter and grows for three or more years is called a perennial. The non-woody ones, or herbaceous perennials die down and lie dormant during the cold season but grow back bigger than ever when the weather warms.
Perennials can be started anytime throughout the growing season, until 2 to 3 weeks before the ground freezes. The later you start them the less chance you'll have of getting blooms the first year. However, if you buy established perennials and plant them early it's a pretty safe bet you'll get blooms before winter. Buying established plants is the fastest way to obtain beautiful results in your garden.
Picking perennials that will thrive in your garden depends on a few things: the climate in your region; the amount of sun that reaches the bed; the plan of garden you want; the length of time it takes them to bloom; and of course, the condition of the plants.
The climate and sun
Is it temperate, cold, wet or hot and dry? See our plant hardiness zone map. Is it sunny, shady or something in between?
Your garden plan
Is it a rock garden with shallow sandy soil; an informal English garden with splashes of tall flowers and clusters of daisies; or a formal effect with gradually increasing heights with maybe some dramatic spikes or ground covering creeper?
Not all perennials bloom at the same time and many only bloom for a few weeks. To ensure you have a continuous flow of blooms in a perennial garden select varieties that will bloom at different times. Irises, for example, are spring bloomers while most lilies flower mid summer with mums blooming in the fall. Consider filling in with some annuals for a smattering of constant summer colour.
Does it look healthy and bushy? Plants with the most flowers are not necessarily the best. Look for those with plenty of new growth at the bottom part of the plant. Look for the Fernlea tag...the choice of experienced gardeners and budding green-thumbers alike!
Until you're ready to plant them keep perennials in the shade and water regularly. Don't let the soil dry out. Plants stored in a dark location like a basement or in the garage longer than a single night or day, can be damaged
The importance of quality soil
Flower gardens need at least 8 to 12 inches of good quality soil to support growth. Regardless of the condition of your soil it can never hurt to add extra organic material - compost, peat moss or manure to your garden each year at the beginning of the growing season. Mix in a little inorganic fertilizer as well. Organic matter works like a sponge, improving the soil's ability to retain most nutrients and water. Inorganic fertilizer completes the balance of nutrients a soil needs to be considered good soil. Good soil makes a good foundation for good plants. See also soil smarts.
Time to transplant
Your bed is made and you're ready to plant... or transplant those established perennials you bought. Make sure they have been acclimatized to the outdoor temperatures for at least a week. This means hardening off the plant little by little from its' protected greenhouse environment allowing them to develop a hardiness to the elements. If you don't harden them off, the shock of the climate change could kill them.
Consider the spacing between the plants to ensure your bed will be able to accommodate more plants in the next year since many will expand in the spring. Planting in the full heat of a sunny summer day is risky. The plant will be stressed in coping with transplanting as well as enduring high temperatures. You could lose the plant. Better to transplant on a shady day or before or after the sun has reached its peak. Water plants well and let them sit for a few minutes before putting them into the ground. This gives the roots a head start on absorbing moisture.
Each planting hole should be twice as wide and twice as deep as the size of the pot the plant is growing in. Gently remove the plant from its pot. Carefully loosen the root ball to allow the roots to spread in the soil as the plant grows.
Position the plant in the hole and firmly pack the soil around the base of the plant. This creates a small depression providing a natural watering hole and forcing the soil to make good contact with the roots. Soak the plant well and finish with a dose of plant starter fertilizer such as 10-52-10 to promote root growth. Keep the plants moist for at least a week until they take. Recently transplanted seedlings (perennials or annuals) need protection from the rain, winds and hot sun for the first week or two that they are in the garden. Still vulnerable to the elements, if they are exposed to strong sunshine or wind they could quickly die.
• Large can with tops & bottoms removed offer excellent protection
• Newspaper tents keep sun and cold air off
• Shingle screens keep wind from damaging your transplants
• Gallon plastic milk containers protect young plants from the cold
On-going care for perennials is quite easy. Aside from a little light house keeping like pulling weeds, there are just four things to do: feed, water, deadhead, and mulch.
Just like people, plants require food on a regular basis. In flowering perennials it's especially important to fertilize weekly during their peak growing period. See plant nutrients for more information.
Water, water everywhere but not a drop to drink! Plants need a good soaking once or twice a week depending on the weather and your climate. A light sprinkling of water is not good enough. Watering plants properly means giving them enough water to reach the roots.
A layer of mulch is as comforting to a plant as a warm blanket on a cold night is to us. Mulching is laying down loose material on the soil surface. Mulching keeps weeds down; keeps the soil warm promoting quicker plant germination and growth; and keeps soil from drying out.
To be most effective mulch should be laid on in the late spring about 3 inches thick and left alone. Mulching allows you to decrease watering frequency by about a third, and eliminates hoeing between the rows. If an organic mulch is used, it will over time improve the soil. Organic mulches include straw, peat moss, sawdust, dry manure, and bark chips. Inorganic mulches include aluminum foil, newspaper, and polyethylene film.
Deadheading is an easy technique to remove fading blooms. Simply pinch off or cut the flower heads as they fade. The plant will then put its energy into producing more flowers instead of seed. You will have a bushier plant with more flower blooms.
Some perennials will have their biggest burst of blooms in the spring but will actually bloom a second time in the fall if you cut off the first flush of flowers as they start to fade. Remember though to keep the leaves and stems intact on the plant. These will continue to soak in the sun's energy putting the good back into the plant's roots.
Select a perennial
Click on a perennial from the list below to see a photo and find lots of growing and plant care tips.
A perennial is any plant that lives for three or more years when it is grown in conditions to its liking is called perennial.