Whether in a commercial installation or residential garden, perennial plants can be successfully used to offer more landscaping choices, distinguish your firm from the competition and create a niche for your landscape business. Perennial plants are complex, and it is best to contract or hire a professional landscape architect for the design phase and train knowledgeable staff in proper maintenance later on.
With a rich history of plant introductions, hybridization and selection, we can now enjoy plants in Georgia that until recently were once found only on a remote mountain slope in Asia or a tropical rainforest in South America. The perennial plant trade offers more than 3,600 species and cultivated varieties, and more are added each year. With such an extensive palette, how do you choose the right plant? Our advice is to follow three simple rules:
You dont have to plant 50 species in one landscape, or always use the latest and most fashionable cultivars – you could make a stunning display with five species or varieties that have been in the trade for 20 years. That said, you should strive to familiarize yourself with new hybrids that have improved tolerance to shade/sun, fewer pest problems, require less water and pruning, and have an extended flowering time. This information can be acquired from books, annual trade conferences and Extension publications (refer to “Additional Resources” at the end of this publication). An excellent way to see how new selections perform is to visit the University of Georgia Trial Gardens located on campus in Athens (http://ugatrial.hort.uga.edu/).
This publication is intended to provide the basics of perennial plant biology, ideas on design and installation, and information on cultivation and maintenance of perennial beds. It should also serve as a quick guide for the most common and recommended perennials for Georgia. Common-sense tips from a professional landscapers perspective are also included.
The term “perennial” in the broadest sense means plants that live for more than two years. This broad definition includes shrubs and trees that retain woody stems above ground in winter, including ferns, cacti, succulents, grasses, bulbs, some herbs and groundcovers. For the home gardener, however, it means a plant with stems that usually die back in winter and a root system from which new foliage and flowers grow the following year. Most perennials have herbaceous stems (e.g., Coreopsis, Achillea, Echinacea, Liatris), but a few develop woody stems (e.g., hardy hibiscus, rosemary). There is also a category of plants, called “tender perennials,” which are annuals that may over-winter occasionally, depending on how severe the winter is (Figure 1). A true perennial has a capacity to survive from one year to the next.
As an avid gardener, I’m always on the lookout for interesting new plants to liven up my backyard. Recently I’ve become very interested in herbaceous perennials. But what exactly are herbaceous perennials and how are they different from other types of plants? I decided to do some research to get the full scoop on these unique plants.
A Basic Definition
Let’s start with a straightforward definition A herbaceous perennial is a non-woody plant that dies back to the ground every winter, but re-sprouts from its root system again in the spring
So herbaceous perennials lack woody stems above ground. Their stems and foliage die back each winter. But underground, they have food storage parts like bulbs, tubers, or rhizomes that let them return every spring.
What Makes Them Different
There are a few key differences between herbaceous perennials and other plant types:
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Annuals – Annuals complete their entire life cycle in one year. They grow, flower, set seed, and die in a single season. Herbaceous perennials can live for many years.
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Biennials – Biennials take two years to finish their life cycle. They grow foliage the first year, then flower, set seed, and perish the next year. Herbaceous perennials bloom annually once mature.
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Woody Perennials – Woody plants like shrubs and trees have permanent woody stems and branches. Herbaceous perennials’ stems wither away over winter.
So the main distinguishing feature of herbaceous perennials is their lack of woody stems paired with their ability to return reliably year after year.
Terrific Examples
Many of our favorite flowers are herbaceous perennials. Some great examples include:
- Daylilies
- Irises
- Peonies
- Astilbe
- Bee Balm
- Coral Bells
- Garden Phlox
- Hostas
- Ferns
- Blanket Flowers
These are just a few of the popular herbaceous perennials grown in gardens. There are hundreds of varieties available with diverse colors, flower shapes, foliage, and growth habits.
Advantages in the Garden
So why should gardeners make room for herbaceous perennials? There are several excellent reasons:
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Permanent Structure – Once planted, herbaceous perennials remain in place for years, providing a permanent backbone and continuity.
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Seasonal Interest – They offer varied interest over the seasons with attractive flowers, foliage, textures, and shapes.
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Lower Maintenance – Compared to annuals, herbaceous perennials are lower maintenance when established.
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Groundcovers & Filler – Some spread to form attractive groundcovers. Others work well as border or edging plants.
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Shade Gardens – Many perennials like hostas and astilbe thrive in shady areas where other plants struggle.
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Erosion Control – Their dense root systems are great for controlling erosion on slopes and banks.
For all these reasons, herbaceous perennials are prized in gardens and landscaping. They offer reliability and multi-season interest year after year.
How to Grow Them
Though low-maintenance once established, herbaceous perennials do have some specific care requirements:
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Most need at least 4-6 hours of sun per day. Some tolerate partial shade.
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Well-drained soil enriched with compost gives them the best start.
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Consistent watering is crucial until plants become established.
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Apply 2-4 inches of mulch around plants to conserve moisture and regulate soil temperature.
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Deadheading spent blooms and cutting back dead foliage in fall keeps plants looking their best.
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Division of overcrowded clumps every 3-5 years revitalizes growth.
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Check planting zone compatibility when selecting perennial varieties.
With proper siting, planting, and care, herbaceous perennials will thrive and delight any gardener for years to come. The effort to establish them is well worth it!
Winter Care Tips
Since herbaceous perennials die back with winter’s arrival, some autumn and winter care is recommended:
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Cut back dead tops in late fall or early spring. Many can be left for winter interest.
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Add a thick layer of mulch over the crown of each plant for insulation.
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Avoid excess fertilization or severe pruning in fall.
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Stake or support perennials vulnerable to heavy snow loads.
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Remove mulch when new growth emerges in spring.
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Delay complete spring clean up if old foliage remains attractive.
With a bit of preparation and care, herbaceous perennials will sail through winter and reawaken vigorously when warmer weather returns.
An Ideal Addition to Any Garden
For their versatility, durability, and lasting beauty across the seasons, herbaceous perennials are an outstanding addition to gardens and landscapes. Their wide variety allows gardeners to create dynamic, evolving beds and borders that improve with time. Once planted, they require minimal upkeep and offer unparalleled rewards. If you’re looking for interesting new plants with staying power, discover the joys of herbaceous perennials!
Marketing Perennials in the Landscape and Managing Customer Expectations
Using perennials in landscape installations can be a rewarding experience for your customers and a profitable one for you; however, there are some common misconceptions regarding perennials that you and your customer need to be aware of.
Perennials are not low-maintenance — they require watering, fertilizing, shaping, deadheading, fall mulching, spring cleaning, dividing, replacing and insect, disease and weed control. Some perennials grow best when divided every few years. Perennial bed renovation should be considered every three to five years. All of these tasks can be built into the maintenance bid and properly addressed from the outset.
Perennials take time to fill space. A popular proverb describes their growth: “The first year they sleep, the second year they creep, and the third year they leap!” Many plants start small and get very large. Make sure you leave them adequate “elbow room” and assure your customer that they are properly spaced.
Customers want flowers and butterflies but they may not recognize that the same sweet nectar brings other insects as well (Figure 26). Bees and wasps may be a nuisance and some people are allergic to their sting. You need to let your customer know that next to the mailbox may not be the best location for that “butterfly magnet.”
Perennial plants can be a valuable addition to your plant palette; they can bring you return customers and boost sales if you follow three simple rules: plant the right plant in the right place, use plants that do well in the area, and spend a few extra resources on maintenance.
The following photos are of commercial installations using perennial plants.
Soil pH and Mineral Nutrients
Since perennials are expected to live in a certain area for many years, it is very important to be sure the soil is amended to fit the plants needs. In addition to organic matter, pay attention to soil pH. Too high or too low soil pH may affect nutrient uptake, stress the plant and reduce the plants chances of surviving more than one year.
Most perennials prefer a pH between 5.2 and 6.7 (slightly acidic). Soil pH affects nutrient uptake (Figure 5). This “Goldilocks” range assures that two important micronutrients — iron (Fe) and manganese (Mn) — are being absorbed by the plant roots in optimal concentrations. If the pH is below 5, both of these elements can interfere with the uptake of other nutrients. If the pH is higher than 7, Fe and Mn can become deficient. Symptoms of nutrient deficiency include yellow (chlorotic) leaf tips and young foliage (Figure 6).
Two other common deficiencies are phosphorus (P) and magnesium (Mg). Phosphorus deficiency typically occurs in winter and manifests as purple or bronze foliage color (on plants with evergreen foliage). Do not direct-supplement with phosphorus; instead, apply a balanced fertilizer, such as 10-10-10, in the spring as leaves emerge and soil warms up. Magnesium deficiency symptoms include interveinal chlorosis of lower leaves (Figure 6). Georgia soils are lower in this important macronutrient; use magnesium sulfate (Epsom salts) to remedy this deficiency. Nitrogen (N) deficiency is typified by chlorosis of older leaves (mild), progressing to overall chlorosis (moderate to severe).
Periods of excessive rain or drought can affect nutrient levels and uptake. In winter, some perennials that have evergreen foliage can become purple or bronze in color. This may be a normal condition in the winter, but a warning sign of deficiencies in late spring. Calcium and magnesium may be depleted. Only a soil test and a foliage test will determine the right ratio of nutrients to add to correct the problem.
A soil test, available through your county Extension office, is the best way to determine which fertilizer analysis is most suitable. As a general guideline, most ornamental plants will benefit from a fertilizer having its primary nutrients (nitrogen, phosphorus and potassium [N-P-K]) in a 3-1-2 or 4-1-2 ratio. A 12-4-8 fertilizer, for instance, is a 3-1-2 ratio, and a 16-4-8 fertilizer is a 4-1-2 ratio. Research shows that phosphorus, the middle number in the analysis, is held by soils and does not leach with rains or irrigation as much as nitrogen or potassium do, so it is usually needed in lower amounts.
The most common types of fertilizer applied to perennial beds in the spring are general-purpose 10-10-10 (N-P-K), 8-8-8 or 16-4-8. Other analyses, however, are sometimes more suitable for a given species (Table 4). The recommendations are based on pounds of nitrogen per 1,000 square feet per season.
- Heavy: 3 applications: 1 pound of 10-10-10/100 sq. ft./season: one at transplant, one three to four weeks later, and another one three to four weeks after that.
- Moderate: 2 applications: 1 pound 10-10-10/100 sq. ft./season: one at transplant and one mid-season.
- Low: 1 application: 1 pound 10-10-10/100 sq. ft. at transplant or in early spring before growth resumes.
Fertility products can be formulated to deliver the plant food over a short- or long-term period. Be sure to use a formula that fits your needs. Spring growth may require fast- acting fertilizer products, whereas summer fertilization may require a slow-release product, including organic fertilizer. Remember that shade areas and sandy soils require different levels of fertility than sunny garden soils.
Below is a simple calculation for how much fertilizer to apply per bed.
- For dry fertilizers (e.g., 16-4-8), divide the percentage of N into 10 (10/16 = 0.6 pounds). The resulting number is the pounds of N to be applied per 100 sq. ft.
- Determine the square footage of the bed (e.g., 5 x 50, or 250 sq. ft.).
- Multiply 250 sq. ft. x 0.6 (the application rate per 100 sq. ft.) then divide into 100 = 1.5 pounds.
- The resulting number (1.5 pounds) is how much 16-4-8 fertilizer to apply to a 5 x 50 perennial bed.
For further information on different fertilizer formulations and application rates, refer to “Care of Ornamental Plants in the Landscape,” UGA Extension Bulletin 1065, and “How to Convert an Inorganic Fertilizer Recommendation to an Organic One,” UGA Extension Circular 853.
Perennials are much like shrubs in that they may require high levels of fertility early in spring or summer, when they put on growth, and low fertility the remainder of the year (Figure 7). The ability of a plant to take up nitrogen is also a function of season. Once leaves are lost to frost, perennials do not need fertilizer.
The 5 BEST HERBACEOUS PERENNIALS For Attracting WILDLIFE to YOUR GARDEN
FAQ
What is a herbaceous perennial?
A herbaceous perennial is a non-woody plant that dies back to the ground every winter but regrows from its root system the following spring. The key identifying features of herbaceous perennials are: Herbaceous perennials differ from other types of plants in a few key ways: Annuals – Annuals complete their entire lifecycle in one growing season.
What is the difference between a perennial and a herbaceous plant?
They grow foliage the first year, then flower, set seed and die the second year. Herbaceous perennials flower every year once mature. So the key difference is herbaceous perennials lack woody stems but regrow from underground year after year, while annuals and biennials have a shorter lifespan. Many popular garden plants are herbaceous perennials.
What is a perennial plant?
Many plant nursery websites have a category called perennials, dedicated to plants that live for more than two years. What you might not realise is that this category never includes trees and shrubs and is in fact mostly dedicated to herbaceous perennials. Herbaceous perennials are distinctly different to trees and shrubs.
What is an example of a herbaceous plant?
Examples of herbaceous biennials include carrot, parsnip and common ragwort; herbaceous perennials include potato, peony, hosta, mint, most ferns and most grasses. ^ Richard N. Arteca (14 February 2014).
What are the identifying features of herbaceous perennials?
The key identifying features of herbaceous perennials are: Herbaceous perennials differ from other types of plants in a few key ways: Annuals – Annuals complete their entire lifecycle in one growing season. They germinate, grow, flower, set seed, and die within a single year. Herbaceous perennials can live for many years.
Are all annuals herbaceous?
However, many perennials are also considered to be herbaceous. Technically, all annual plants are herbaceous, because an annual is a non-woody plant. Annuals take it a step further and die altogether at the end of their lone growing season, both above the ground and below it.