Garden Guy: Perennials for Beginners

By Bruce Bennett

I have been reminded by several readers that not all home gardeners are experienced and that some would appreciate an occasional beginner-level gardening article. 

With that being the case, let’s start with a column on a basic unit of urban landscapes - the perennial. By definition, perennials are hardy plants that have a minimum lifespan of three years (although most of them are good for twenty years and longer). 

These plants are herbaceous and have flowers, leaves and stems that die back each fall and have new growth that arises from the roots each spring. Foundation plants of a garden, perennials can provide years of enjoyment and long-lasting beauty. However, before adding them to a garden, there are some guidelines for the new gardener…..

Photo by extension.osu.edu

Prepare and Test Your Soil 

It is important to do some initial soil preparation. After you choose the spot you want to landscape, check the soil drainage by digging a ten-inch deep hole and filling it with water. 

The next day fill it with water again. If all the water has not drained out in eight hours, the drainage is poor and you should consider constructing a raised bed or adding perennials which are able to handle damp soils. 

Add three to four inches of compost or aged manure to planting area and dig int in to a depth of 8” – 12”. This process will build up or “raise” the bed. Next, test the pH of your soil. 

Test kits can be purchased at garden centers and free testing may be a service of your county’s Extension or conservation department. In the Seattle area, look to the King Conservation District. Once you have the test results, make the recommended amendments to the soil. The local Master Gardeners program can help to interpret your test results.

Right Perennials 

Before buying do some researching. Decide what kind of garden you want; cottage garden, rock garden, mass planting of color, herb garden. Are you going to use bulbs or ornamental grasses? Is your flower bed in mostly sun or shade? 

It is important to have the right growing conditions for your perennials. A shade plant may not survive in the hot sun. A plant that likes direct sun may not flower properly in a shady spot. Make sure the plants are hardy for your area otherwise you are squandering your time and money.

Check the flowering times of different perennials. Pick plants and bulbs with different blooming periods so you have a succession of bloom during the spring, summer and fall. Look for ones that have longer blooming periods. 

Most plant catalogs (and, definitely, the Internet) have this information and will make it easy for the novice to select the right plants for a succession of blooms. You can also mix annuals (plants that live only one season) with your perennials. 

The annuals will help brighten the garden during the periods when some of the perennials stop blooming and will act as ‘fillers’ until the newly planted perennials mature and fill-out.

Purchase your perennials Here there are many choices: garden centers, garden club sales, herb farms, catalogs or better yet, get plant divisions for free from friends, neighbors and relatives who are dividing their plants. 

Perennials are more expensive than annuals, but you only have to buy a few plants of each variety because, over the years, perennials will grow and spread. 

Make sure the plants are healthy looking. You want plants that are dark green and compact—avoid plants with thin, yellowing stems and leaves or ones that may be harboring insects. Read the directions on the plant tags to see if they do best in sun or shade, how far apart to space them, and how tall they will get.

Start Planting 

Plant in clumps or groups, spacing the plants as the directions recommend and keeping in mind the height of the plants. Plant according to heights starting with the tallest plants in the back of the bed down to the shorter, edging plants in the front. Of course, there are always exceptions. 

Tall plants that can easily be seen through (think Brazilian Verbenia, Verbenia bonariensis at left) can provide an aesthetic screen through which to view the planting bed behind them. Large plants like ornamental grasses do better planted as specimens by themselves since they will grow very large over the years. 

Begin planting by removing your plants from their growing containers leaving as much of the moist soil around their roots as possible. Dig a hole deep enough so that the top of the root ball is level with or just above the surface of the ground.

Before setting the plant in, drench the soil in the planting hole and then fill in with soil around the plant. Water on a regular basis until the plant is established and during dry spells. Water needs to reach the roots of perennials so use a soaker hose, drip irrigation or oscillator with water timers. Your goal is to provide all plants with 1” or water once a week (or more when the area experiences hot, dry spells.

Photo by gardening.wsu.edu

Mulch 

This gardening aid will keep the soil moist and warm and cut down on weeding. Bark, pine needles or shredded leaves are good organic mulches. You can also use gravel or black plastic landscaping material. Definitely stay away from the inorganic shredded and dyed rubber mulches.

Deadhead 

Remove old flower heads or cut back plants to keep them neat looking after their blooming period is finished. With many perennials, deadheading will cause reblooming and extend the visual interest of the plant.

Fertilize 

This should be done each spring as plants come to life and begin growing.

Divide 

Every three to five years your plants will probably need to be divided as they will get overcrowded with have bare centers. Divide them into clumps of three to five shoots. Do this when plants are dormant in the spring or fall.

Follow these steps and you are on your way to establishing a beautiful garden. When fall comes, your plants will die back, but what a thrill when they are viewed breaking the soil each spring. With perennials, a little investment in time and money now can give you virtually a lifetime of enjoyment. Happy gardening all!

Contributing garden columnist, Bruce Bennett, is a Washington State University Certified Master Gardener, lecturer and Seattle-area garden designer. 

If you have questions concerning this article, want to read more beginner-gardener directed articles or, if you want to suggest a topic for a future column, contact Bruce at gardenguy4u@gmail.com.