Perennials: A Complete Guide


Perennials are a great option for any garden. For the serious gardener, annual or biennial plants just might not be cutting it anymore. The process of planting, nurturing, and (after the year’s up), pulling your once lively flowers out of the ground to start anew, can become daunting. So, how about perennials?

So, what exactly are perennials? Perennials are plants that live for more than 2 years before they wither and die completely. Herbaceous perennials are the main category addressed by gardeners. These plants die off to the ground – their roots surviving – and bloom again for the following seasons.

Luckily, perennials are the fighting few that last many years before dying; and we’re here to provide you with everything you need to know to grow them. In the next few sections, we’ll be covering the different types of perennials, information on proper planting, and how you can help them, to help you.

Why You Should Grow Perennials

As we mentioned in the introduction, if you choose to fill your garden beds to the brim with annual flowers, you can expect complete die-off come winter. Which leads to having to clean out the entirety of your beds. It also means that when planting season rolls around, you’ll have no other choice but to start the process all over again.

But with perennials, maintenance won’t be so often or as strenuous. Because perennials will survive for more than 2 years, there will be no need for complete removal down to the root – just tidying up dead leaves and blooms. And once spring comes, you won’t have to do any planting, as the roots of perennials will spring forth new, colorful life.

Not only will maintaining your garden become easier but once these plants are initially established in your garden, they will readily spread seed and fill the empty spaces in your soil, bringing more color and fullness year after year.

Planting Perennials

Planting perennials is a simple process that we’ll go over step-by-step in the following sections. You’ll find that after initially establishing these plants, they’re quite hardy and do well with minimal upkeep.

Step 1: Preparing Fertile Soil

Because perennials feed off of the same soil nutrients year after year without the same nutrient replacement as annual flowers receive, it’s a good idea to prepare your perennial garden bed with as much organic material as possible for sustenance.

Compost is an excellent source of nutrients and can be comprised of fallen leaves, vegetable and fruit matter, lawn clippings, or animal manure. For the best results, you may want to prepare your soil months in advance. If you’re planting in the spring, prepare the soil in the fall. Similarly, if you’re planting in the fall, try to prepare the soil in the summer.

Step 2: Gathering Your Perennials

The next step in any type of gardening is to buy your plants. When buying perennials, it’s a good idea to start off with plants in 4-inch pots. This will save more money than if you buy larger perennials. Plus, the smaller, 4-inch perennials will catch up to any big perennials you have within a single growing season.

Step 3: Water Before Planting

Once you have your (still potted) plants, placed where you want them in the bed, lightly water them to keep the roots moist. You never want to plant perennials with dry roots.

Step 4: Dig the Holes

Before you dig, determine whether or not you’re planting in a large garden bed. You never want to dig prematurely, as you risk drying out the inner soil. Dig a hole only when you’ll be planting the perennial directly after.

The holes for your perennials should be slightly deeper and twice as wide as the pot the perennial is in. If you have any compost, you can place some of that in the hole. If the soil is already dry, be sure to water the soil before planting to moisten the dirt.

Step 5: Unpot the Perennial and Prepare the Roots for Planting

Gently grasp the stem of the plant and slowly remove it from the pot. If you notice that the roots are compact, tease, and slightly loosen the roots. This will encourage better overall growth and establishment in the soil.

Scoop the fallen soil from the pot into the hole and keep any soil from the pot that remains on the roots for added nutrients.

Step 6: Place the Perennial in the Hole

After you’ve dug the hole, set the perennial inside. Make sure the hole isn’t too deep. You can do this by ensuring that the crown of the plant is not below the edge of the hole. The crown, where the stem and the potted dirt and roots meet, should not be buried beneath the soil.

Step 7: Fill the Hole

Begin filling the hole with soil. Once the hole is filled halfway, water the soil to moisten it. Then, continue to fill the hole until it is filled completely. Gently pat down the topsoil with your hands to secure it around the plant.

Step 8: Water in and Mulch

The final step is to water the perennial and mulch the plants thoroughly. Be sure to water the perennials enough so that the hydration reaches the roots. Place organic mulch in a ring around each of the perennials, careful not to smother the stem and crown of the plants. 

Shredded bark mulch is a great option for perennials, as it will begin to break down over time, adding even more nutrients to the garden bed for your plants to thrive on.

Commonly Asked Questions About Planting

In this section, we’ll briefly cover the most common questions that are asked when planting perennials and condense some of the information in the previous sections.

How Deep Should I Plant My Perennials?

As with any plant, perennials should sit no deeper than their crown (the place where the stem and roots meet) in the ground. As a general guideline, a hole for perennials should be slightly deeper (only an inch or two) than the pot it was planted in, but twice as wide as the pot.

Digging a hole too deep could result in stem rot, which would kill your plant completely and prevent it from growing and reproducing year after year.

Refer back to Step 4 in the above section for more information about digging holes for your perennials.

How Much Water do Perennials Need?

After you’ve planted your perennials, you’ll need to soak the plants thoroughly. For upkeep, watering once a week will suffice just as long as it’s a deep watering.

Generally, perennials thrive best with more infrequent, deep watering rather than light watering daily. Deep watering will encourage growth. Water either early in the morning or in the evening to avoid the high temperatures and sun exposure of midday, which may result in over-drying.

How Much Space do Perennials Need?

Usually, you can find planting instructions on individual perennial plant pots. However, if you can’t locate specific planting information, there is a general rule of thumb for different-sized perennials:

  • Small perennials should be spaced 6 to 12 inches apart.
  • 2 to 3-foot tall perennials should be spaced 12 to 18 inches apart.
  • Taller perennials should be spaced 18 to 36 inches apart.

Planting juvenile perennials too close together could result in overcrowding as they grow. Overcrowding leads to a competition for sunlight and nutrients in the soil, which could result in some of your perennials dying off. 

How Do Perennials Help the Soil?

Because perennials typically have deep roots, they can help the soil by minimizing the effects of erosion. As older perennials wither and die, they have already produced offspring, which gives you more beautiful flowers and, in turn, provides the soil with more nutrients from the older plants that have died.

How Long Do Perennials Last?

A single perennial plant can last more than 2 years. However, they constantly spread seed, giving you a long-lasting supply of perennials that could endure a decade or more from the same family of plants.

After-Planting Perennial Care 

Once you’ve gotten all of your perennials situated, there are three things you can do periodically to ensure a healthy bed of perennials: fertilize, mulch, and weed control. Let’s take a look at each individually.

Fertilization

If you have not prepared the soil with fertilizer beforehand (as outlined in the above planting guide), then your perennials may benefit from fertilization.

However, be cautious with how much fertilizer you use. Too much fertilizer will keep perennials from blooming. According to research by the University of Illinois, perennials do best in gardens that contain 1 pound of Nitrogen per 1,000 square feet.

The most beneficial fertilizers for perennials have a formulation of 12-12-12, 10-10-10, or 5-10-5. These numbers stand for the ratio of Nitrogen-Phosphorous-Potassium in the mix.

Mulching

After the initial planting, you should mulch immediately. Then, continue with yearly upkeep, adding new mulch to your perennial garden bed(s) so that the thickness doesn’t exceed 2 inches.

Weeding

When you notice that weeds are beginning to grow in your perennial beds, it’s best to address the issue before it gets out of hand. Weeds aren’t needy and will thrive practically anywhere, taking over your gardens and possibly smothering your small perennials.

As you weed, be sure that you are removing the plants down to the root to keep them from growing back.

The Best Perennials for Certain Conditions

Most perennials can grow fine no matter where they’re planted, just as long as they’re given the proper soil conditions and are planted in the right season. In the next few sections, we’ll be going over the best perennials for specific conditions and preferences.

Perennials that Like Shade

Whether you’re looking for perennials that can fill in gaps in your garden or your yard is simply too shady for sun-loving plants, these perennials that like shade will do just the trick:

  1. Spiderwort: These gorgeous plants sprout deep purple blooms atop golden foliage. They bloom from spring to the first frost of fall and do best in areas of part-shade where they can receive 3 to 6 hours of morning or evening sunlight per day.
  2. Ferns: It’s no surprise that ferns are often found in shady forests. They thrive tremendously in part-shade and full-shade conditions and boast lovely, huge green leaves. 
  3. Ground Orchid (Bletilla): This early spring flower is dressed in various shades of white, pink, and purple blooms. It does great in warmer climates and thrives in shady conditions. 
  4. Lily of the Valley: This shady perennial holds dazzling white pendant bell-shaped blooms. Be careful, because this hardy plant will spread rapidly. Great for groundcover. 
  5. Viola: These deep purple and multicolored flowers love part to full shade. They bloom in the spring and can have a dainty fragrance. 
  6. Lenten Rose (Hellebore): These plants are evergreen and do well in full shade. They readily spread, so it’s a good idea to pick a spot you won’t mind if they take over. 
  7. Foamflower: True to the name, these flowers boast white blooms that look similar to foam. They bloom in spring and summer, and their foliage often contains red or purple markings. 
  8. Coral Bells (Heuchera): This maroon plant is covered in fluffy foliage. In the summer, small spikes with flowers emerge. 

Each of these perennials is either full-shade or part-shade plants. Be sure that they receive three to six hours of sunlight, only in either the morning or the evening. Midday sun is often too harsh on shade perennials. 

Perennials that Bloom All Summer

This list of perennials does well in hotter environments and blooms gorgeous flowers all summer long. Here are the best perennials for summer gardens:

  1. Hardy Hibiscus: Hardy Hibiscus is one of the most popular perennials for summertime. These tropical plants sport huge blooms that can reach a foot across. They’re wonderful full-sun plants, they attract hummingbirds and butterflies, and they come in gorgeous bright colors.
  2. Black-Eyed Susans: These perennials would make a sunny addition to any summer garden. With their blinding yellow petals and deep brown centers, these flowers not only catch the eyes of onlookers but of butterflies as well. They’re rabbit and deer resistant and bloom from July to September.
  3. Lavender: Not only does lavender have a soothing scent, but it’s also a hardy plant that does well during the summers and creates beautiful purple blooms. It attracts butterflies and likes full sun.
  4. Bee Balm: Bee balm is a favorite among (you guessed it) bees, hummingbirds, butterflies, and other pollinating wildlife. They can grow up to 4 feet tall and are arrayed with large balls of purple blooms.
  5. Shasta Daisies: These daisies are adorned with large white petals that bloom until early fall. They’re a classic summer flower and will certainly brighten up your perennial gardens. 
  6. Coneflowers: These full-sun-loving flowers are deer resistant, attract butterflies, and come in a variety of bright, summery colors like orange and red.
  7. Coreopsis: Coreopsis’ can grow up to 3 feet tall; they are clothed in bright yellow, orange, or multi-colored petals, and attract birds and butterflies. They’re a wonderful all-around option for the perennial summer garden.
  8. Phlox: Phlox plants have a wonderful scent to them and are generally comprised of pinkish and purplish tones. They attract butterflies, and their blooms are in glorious clusters of color. They like full sun.

Most of the above flowers prefer full sun but can tolerate partial shade if necessary. Watch out for extremely high temperatures and be sure to water whenever you notice the soil has become dry.

Perennials that Bloom During the Fall

If fall blooms are more your speed, these breathtaking perennials will undoubtedly liven up your harvest time gardens:

  1. Goldenrod: Boasting the gorgeous fall colors of deep yellows and golds, Goldenrods are tolerant of heat and are easy to care for. 
  2. Helenium: For additional fall color, Heleniums sport dashing deep reds, oranges, and yellow tones. They love the sun and can grow up to 4 feet tall. 
  3. Mums (Chrysanthemums): Mums are some of the most colorful garden perennials available. They come in an array of colors, including orange, yellow, and red. They prefer part or full sun. 
  4. Sedum: This green perennial can virtually care for its own. Just plant it and basically forget it (aside from a watering now and again). They need a sunny spot to thrive. 
  5. Aster: These hardy plants can grow up to 4 feet tall and come in a variety of colors, including white, purple, blue, or pink. They’re densely-packed flowers, making them wonderful for clusters of color. 
  6. SwitchGrass (Prairie Fire): This ornamental grass is complete with deep orange and red blades atop dark green stems. They provide cover for birds and look lovely when swaying in the autumn breeze. 

The majority of these plants prefer part or full sun. Watch out for freezing temperatures and be sure to water when the soil dries. 

Final Thoughts

Perennials are astounding flowers that come in a variety of shapes, sizes, textures, and colors. They’re tough plants that can withstand years of living in a single garden, and they spread their seeds openly to give you a continually gorgeous yard. 

With a little upkeep and work initially, you’ll have an established perennial garden to last you years to come.

Eyerly Family

The Eyerly Family is a family of 8 that loves gardening. Over the past several years we have been applying what we learn about gardening to our own 16x16 raised back yard garden. Our garden is very prolific and we grow a wide variety of vegetables which we love to eat! Click here to learn more about the Eyerly Family.

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