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Designing and Preparing a Perennial Bed

Description/Purpose:

Perennial beds and borders can add beauty and value to your home. They contain plants that return year after year. A perennial bed stands by itself in a turf area and can be viewed from all sides. A perennial border is designed to be viewed from one side and is backed by shrubs or a fence. Beds and borders can be an attractive addition to a residence or commercial business by providing color, texture and year-round interest. Planning a perennial garden takes time, knowledge and effort. The planning and designing stage is often overlooked. This often results in a haphazard collection of plant materials. Designing the perennial bed on paper, before beginning installation, will ensure that the perennial bed design will be successful.

Preparing a perennial bed properly can improve soil structure and fertility, encouraging your new perennials to easily adapt after transplanting.


Perennial Bed Design

Supplies, Equipment and Tools:

  • 1/4 inch graph paper (8 1/2 x 11)
  • #2 pencil or mechanical pencil
  • Eraser
  • Straight-edge (a ruler or drafting triangle works well)
  • Tracing paper
  • Tape measure
All supplies are available at office or art supply stores.

Site Considerations:

Evaluating your site is key to the success of your perennial bed/border. For more information on design see Base Plan for Site Survey and Site Analysis in the Design section of SULIS.

Views

To obtain more enjoyment from the perennial bed, position it in a location that can readily be seen from a window, patio or porch. Once you have decided on the location, evaluate it for the following:

Soil Type

The type of soil in your perennial bed is important in plant selection. The soil type determines the type of plants you can use. For example, Stonecrop (Sedum spp.) grows best in well-drained soils such as sandy loam soil.

Improving the soil on your site will improve the performance of your new perennials. The ideal soil for a perennial bed is a medium loam, which has a fine crumbly texture. This soil type retains moisture without becoming saturated and contains a balance of nutrients. Soil texture is determined by the size of the soil particles. Sandy soil has larger soil particles and does not retain moisture well, and although it is easy to dig, it is low in fertility. The other extreme, clay soil has fine soil particles becomes saturated easily, drains slowly, is harder to dig and work but is usually fertile. Loam soil has a medium texture.

It is best to have your soil tested to determine its structure and pH. For information on soil testing and pH go to http://www.extension.umn.edu/yardandgarden/YGLNews/YGLN-Aug1599.html. For information on soil testing go to http://www.extension.umn.edu/distribution/horticulture/DG1731.html.

Incorporating organic and inorganic matter with the soil can help improve soil structure, aeration, moisture retention and soil fertility. Organic additives include well-rotted manure, leaf mold, composted shredded bark and compost. Inorganic additives include coarse sand and lime. Coarse sand, when incorporated with heavy clay soils, lighten and improve drainage. Lime can improve the structure of clay soils by breaking it up. Lime is alkaline so avoid using it where you plan to plant acid loving plants. For additional information on soil amendments see Amending Soils for Perennial Beds; for selecting commercial compost go to http://www.sustland.umn.edu/implement/compost.html.

Plant Lists for Various Soil Types (not exhaustive):

Well-Drained (sandy) Soil
Common Name Latin Name
Ornamental Onion Allium senescens 'Glaucum'
Butterfly Weed Asclepias tuberosa
Violet Queen New York Aster    Aster novi-belgii 'Violet Queen'
Rockcress Aubrieta deltoidea 'Purple Gem'
Sweet Woodruff Galium ordoratum
Blue Oat Grass Helictotrichon sempervirens
Tall Bearded Iris Iris germanica
Smooth Penstemon Penstemon digitalis
Creeping Phlox Phlox subulata var. atropurpurea
Tiger Stripe Foam Flower Tiarella x 'Tiger Stripe'

Loam
Common Name Latin Name
Maiden Hair Fern Adiantum pedatum
Greek Anemone Anemone blanda
Wartburg Star Aster Aster tongolensis 'Wartburg Star'
Clematis Clematis hybrids
Bee Delphinium Delphinium elatum
Foxglove Digitalis grandiflora
Crested Gentiana Gentiana septemfida
Francee Hosta Hosta 'Francee'
Japanese Spurge Pachysandra terminalis
Hybrid Sage Salvia x superba

Clay
Common Name Latin Name
Threadleaf Coreopsis Coreopsis verticillata
Giant Sunflower Helianthus giganteus
Daylily Hemerocallis spp.
Silver Grass Miscanthus sinensis
Blue Stocking Bee Balm Monarda didyma 'Blue Stocking'
Grey-headed Coneflower Ratibida pinnata
Lamb's Ear Stachys byzantina
Stonecrop Sedum spp.

Light Conditions

Observe the light conditions in the area where the bed will be placed. Is it in a sunny, partly sunny, or shady area? How many hours of sun or shade does it get per day? Full Sun areas receive 6+ hours of direct sunlight per day. Part Sun areas receive 3-6 hours of direct sunlight per day, and Shady areas receive no direct sun. The hours of sun per day in the bed/border determines the type of plants that can be used. A shade-loving plant will quickly wilt and die if placed in a sunny location. Conversely, a sun lover will become leggy and will not produce flowers if placed in a shady spot. Placing plants in the wrong type of light is a common cause for plant failure.

Plant Lists for Various Light Conditions (not exhaustive):

Full Sun
Common Name Latin Name
Yarrow Achellia spp.
Wormwood Artemesia spp.
Yellow False Indigo Baptisia tinctoria
Globe Thistle Echinops ritro
Purple Coneflower Echinacea purpurea
Sea Holly Eryngium alpinum
Blanketflower Gaillardia x grandiflora
Creeping Phlox Phlox sublata
Stonecrop Sedum spp.

Part Sun
Common Name Latin Name
Lady's Mantle Alchemilla mollis
Astilbe Astilbe x chinensis
Heartleaf Bergenia Bergenia cordifolia
Lily of the Valley Convallaria majalis
Bleeding Heart Dicentra spectablis
Blue Fescue Festuca glauca
Plantain Lily Hosta spp.
Petite Delight Bee Balm Monarda didyma 'Petite Delight'

Shade
Common Name Latin Name
Aconite Monkshood Acontium napella
Carpet Bugleweed Ajuga reptans
Columbine Aquilegia spp.
Wild Ginger Asarum canadense
Young's Barrenwort Epimedium x youngianum
Hakonechloa grass Hakonechloa macra
Virginia Bluebells Mertensia virginica
Solomon's Seal Polygonatum odoratum
Lamb's Ear Stachys byzantina

Moisture

Is the site wet, slightly moist, dry? Careful consideration of soil moisture content is crucial to plant survival. Placing the proper plant for the moisture conditions available will contribute to healthy, vigorous plants.

Plant Lists for Various Soil Moisture (not exhaustive):

Wet
Common Name Latin Name
Aconite Monkshood Acontium napella
Heartleaf Bergenia Bergenia cordifolia
Marsh Marigold Caltha palustris
Siberian Iris Iris sibirica
Ligularia Ligularia dentate
Virginia Bluebells Mertensia virginica
Catmint Nepeta spp.
Japanese Primrose Primula japonica
Meadow Rue Thalictrum spp.
Spiderwort Tradescantia x andersoniana

Moderate (consistent moisture)
Common Name Latin Name
Windflower Anemone spp.
Bleeding Heart Dicentra spectablis
Wintercreeper Euonymus fortunei
Meadowsweet Filipendula vulgaris
Crested Gentiana Gentiana septemfida
Dame's-rocket Hesperis matronalis
Coral Bells Heuchera sanguinea
Lamium Lamium maculatum
Lavender Lavandula angustifolia
Peony Paeonia lactiflora

Dry
Common Name Latin Name
Yarrow Achellia spp.
Rock Cress Arabis blepharophylla
Purple Coneflower Echinacea purpurea
Young's Barrenwort Epimedium x youngianum
Silver Grass Miscanthus sinensis
Coneflower Rudbeckia spp.
Goldenrod Solidago spp.
Lamb's Ear Stachys byzantina
Adam's-needle Yucca filamentosa

Bed/Border Shape, Size and Style:

The nature of the site and its surroundings should be considered before deciding what type of perennial bed/border to make. What shape should the planting bed be? How large? The answers to these questions are based upon the style of garden desired, available space, and maintenance requirements.

Style

Formal designs consist of straight lines and hard edges. Geometric curves soften the formality. Formality can be softened with plants that have a trailing or loosely mounding habit.

Formal Design Style
               Formal Design Style
               SULIS - http://www.sustland.umn.edu/design/balance.htm

Informal designs consist of free-flowing curves. Curving borders help to soften the hard-edged, right-angled planes of the house.

Informal Design Style
               Informal Design Style
               SULIS - http://www.sustland.umn.edu/design/balance.htm

Principles of Design:

Design principles are basic guidelines used to create order in a perennial bed/border. They consist of simplicity, variety, balance, emphasis, sequence, and scale.

Simplicity

Simplicity refers to limiting the different types (shapes) of plants in a design. If too many different types of plants are used, the border will appear disorganized and messy.

Variety

Variety creates visual interest without sacrificing the simplicity of the design. Using a variety of textures, colors, heights, and bloom times will keep the bed from appearing dull.

Balance and Emphasis

Balance is used to keep the border from looking lop-sided. For example, placing all of the tall or coarse-textured plants on one end of the border would be poor balance. Instead, distribute tall or coarse-textured plants throughout the border to create emphasis. Emphasis in a design momentarily stops the eye and makes the bed more interesting.

Sequence

Sequence is a gradual transition from one area to another within the border. Placing a fine-textured plant next to a medium-textured plant is an example of good sequence. An example of poor sequence is placing a fine-textured plant next to a coarse-textured plant.

Scale

Scale is the size of the plant relative to other plants in the border, and relative to the size of the border. A 7' ornamental grass would look out of scale next to a 1' perennial in a 3' x 3' bed.

Addition information on design principles can be found in principles of design in Design section of SULIS under The Completed Landscape Design.

Plant Selection - Elements of Design:

Elements of design are criteria used for selecting and organizing plants. Applying these criteria you will be more likely to use a wider variety of plants and your design will look more professional.

Primary Elements:

Height and Width

These two elements are very important in plant selection. Vertical elements add dimension and pizzazz to a design. Mature plant width determines horizontal space requirements in the border. To keep the plants from becoming overcrowded in the border, design with the plants' width in mind. Allowing enough space for plants to grow also cuts down on maintenance and disease. Varying the height and width of plants (often called layering) creates depth and emphasis within the bed and keeps the viewer's eye from getting bored.

Texture

Texture refers to the fineness or coarseness of a plant. Fine-textured plants melt into the background at a distance, but are delicate close up. Visual detail is observed in medium-textured plants, even at a distance. Coarse-textured plants offer punctuation in an otherwise dull border. Combinations of texture are present in some plants. Heuchera spp. has coarse-textured foliage and fine-textured flowers. Providing a variety of textures in the perennial bed will keep things lively. For more information, visit Cornell University Extension Service's online article on texture.

Plant Lists for Various Textures (not exhaustive):

Fine
Common Name Latin Name
Yarrow Achillea millefolium
Flowering Onion Allium senescens
Columbine Aquilegia spp.
Threadleaf Coreopsis Coreopsis rosea
Alwood Pink Dianthus x allwoodii
Bleeding Heart Dicentra spectablis
Dropwort Filipendula vulgaris
Prairie smoke Geum triflorum

Medium
Common Name Latin Name
Wild Ginger Asarum canadense
Butterfly Weed Asclepius tuberosa
Heartleaf Bergenia Bergenia cordifloia
Blue Chips Bellflower Campanula carpatica 'Blue Chips'
Foxglove Digitalis grandiflora
Sweet Woodruff Galium ordoratum
Daylily Hemerocallis spp.
Francee Hosta Hosta 'Francee'
Siberian Iris Iris sibirica
Bee Balm Monarda didyma

Coarse
Common Name Latin Name
Chrysanthemum Chrysanthemum spp.
Elegans Hosta Hosta sieboldiana 'Elegans'
Blazing Star Liatris pychostachya
Ligularia Ligularia spp.
Poppy Papaver orientale
Solomon's Seal Polygonatum odoratum
Stonecrop Sedum spp.
Lamb's Ear Stachys byzantina
Adam's-needle Yucca filamentosa

Form

Plants have basically three shapes: spiky, mounded, and prostrate (flat). Spiky plants stand stiffly upright. They add vertical interest and dimension. Mounded plants add softness and continuity to the design. Prostrate plants fill in the gaps and are great at the front edge of the border.

Example of height, texture, and form.

Figure 1

Plant Lists for Various Forms (not exhaustive):

Spike/Upright
Common Name Latin Name
Yarrow Achillea millefolium
Monkshood Acontium napellus
Hollyhock Alcea rosea
Big Bluestem Andropogon gerardii
Butterfly Weed Asclepias tuberosa
New York Aster Aster novi-belgii
False Indigo Baptisia australis
Feather Reed Grass Kalamagrostis x acutiflora
Lily Lillium spp.
Smooth Penstemon Penstemon digitalis

Mound
Common Name Latin Name
Lady's Mantle Alchemilla mollis
Whirlwind Anemone Anemone x hybrida 'Whirlwind'
Silver Mound Artemesia schmidtiana 'Silver Mound'
Wild Ginger Asarum canadense
Little Boy Blue Pink Dianthus 'Little Boy Blue'
Blue Fescue Festuca glauca
Marsh Marigold Caltha palustris
Cranesbill Geranium sanguineum
Blue Oat Grass Helictotrichon sempervirens
Blue Angel Hosta Hosta 'Blue Angel'
Blazing Star Liatris spicata

Prostrate
Common Name Latin Name
Snow-on-the-Mountain Aegopodium podagraria
Bugleweed Ajuga reptans
Bloodstone Thrift Armeria maritima 'Bloodstone'
Threadleaf Coreopsis Coreopsis rosea
Sweet Woodruff Galium odoratum
Japanese Spurge Pachysandra terminalis
Creeping Phlox Phlox sublata
Golden Carpet Sedum Sedum acre

Color

Perennial plants bloom only once a year, so plan for more than one season. Select a combination of plants, so that you will have at least one or two plants blooming in each season (spring, summer or fall). Also, select a few plants that have intriguing seed-pods that will provide winter interest, such as Sedum spp, and ornamental grasses such as Blue Fescue, Blue Oat Grass, and Feather Reed Grass. Place plants so that spring, summer, and fall bloomers are evenly distributed throughout the garden to provide a succession of blooms.

Choose color combinations that are pleasing to you. Vibrant colors, such as red, orange and yellow stand out in the garden. Cool, soothing colors, such as blue, green and purple recede into the background. For more information on use of color in the garden see Texas A&M University Extension Service's Color Rotation, Cornell University Extension Service's Introduction to Color, and Iowa State University's Garden Color.

Secondary Elements:

Selecting plants using secondary elements of design is essential for the success of the perennial bed. Information on drought tolerance, insect and disease resistance, soil adaptability, full sun or shade tolerance, and moisture tolerance can be found in Secondary Elements of Design under Elements of Design in the Completed Landscape Design. Named cultivars of a plant are usually superior in appearance, performance and disease resistance than the species. For example, Phlox paniculata 'David' is more resistant to powdery mildew disease than Phlox paniculata.

Choosing plant materials based on secondary elements of design can be done using the Plant Selection program.

Many books such as Perennial Combinations by C. Colston Burrell and Pictorial Guide to Perennials by M. Jane Coleman Helmer and Karla S. Decker Hodge are good sources for plant selection. Visiting the local nursery or garden center is also helpful in selecting plants that appeal to you.

Other Design Considerations

Group plants in odd numbers. Odd numbers are more pleasing to the eye. Repeat groups periodically throughout the bed to keep the eye moving and to provide rhythm. Rhythm (and repetition) is important for tying the plants together and unifying the border.

If the border is too wide to reach across without stepping on plants, an access path behind the border is necessary. A mulch path over newspapers works well.

Use edging to eliminate turf grass infiltration. For information on installing edging see Installing Poly Landscape Edging.

Measuring the Site and Drafting the Plan:

Measuring the Site

Measure the area of the proposed bed/border. Record the measurements.

Drafting the Plan

Draw the shape of the bed to scale, on graph paper, using the measurements as a guideline. This drawing will be your base plan. An explanation of the base plan can be found in the Design section of SULIS.

Select plants based on your preferences, and primary and secondary design elements. Make a list of selected plants along with height, width, form, texture, color, and bloom time.

Place tracing paper over the base plan. Draw plants, experimenting with combinations and placement. When you are satisfied with the selection and placement of plants, draw them (to scale) on the base plan. Label all plants.

The completed drawing/design will facilitate proper plant placement during the implementation portion of the perennial bed/border.


Perennial Bed Preparation

Tools/Equipment:

  • Flat Edge Spade, for cutting and digging out the bed
  • Herbicide, such as Round-Up, to easily kill perennial weeds and grasses
  • Garden tiller, to incorporate organic matter into the soil
  • White Spray Paint, to mark the outline of the proposed bed
  • Garden Rake, to break-up large soil clumps and smooth the soil
  • Edging Material, several types are available including steel, aluminum and poly edging.
Step-by-Step Process:
  1. Call Gopher State One Call to mark any underground utility lines, Twin City Area 651-454-0002, MN toll free 1-800-252-1166. Underground utility lines such as electric, gas, water or sewer lines can be inches below the surface.

  2. Use a garden hose to mark your bed line. This process helps you to visualize your bed line. Be sure the radius of the curves will allow easy use of the lawn mower.

  3. Once you decide on a bed line, mark the bed line with white spray paint.

  4. Clear the site of weeds. If the area is heavily infested with weeds, an herbicide will save you a lot of time and work. There are two types of herbicides. Contact herbicides are effective only on the parts of the plant that come in contact with the chemical. Systemic herbicides are carried to the root system of the plant; these are especially useful for perennial weeds. Round Up is a systemic herbicide and works well. Wait one week after the application before breaking ground.

    The best time to apply an herbicide is when the weeds are growing, preferably late spring or early summer. Always read the manufacture's instructions and use the suggested rates and quantities. Never use an herbicide on a windy day. Be sure to wear protective gloves and clothing when recommended by the manufacturer.

  5. When the site for your perennial bed is free of weeds, you can begin the task of digging out the bed. Do not dig when the soil is wet, you may damage the soil structure. If you are dealing with heavy clay soils you may want to break the task into portions over a couple of days. You will feel more energetic and enthusiastic about the job.

  6. Outline the bed with a flat edge spade, slicing straight into the ground to the spades depth.

    Figure 2
    Adapted from Great Garden Shortcuts

  7. Make parallel cuts 6-8 inches apart across the bed.

  8. To dig the bed, work down one line turning small chunks of soil over and chop up large portions of the soil with the spade or shovel.

    Figure 3
    Adapted from Great Garden Shortcuts

  9. Once the entire bed has been dug, organic matter can be spread over the planting area. Let the organic matter settle fir a couple of days then till the soil to incorporate the organic matter. Please visit the University of Minnesota Extension Service web site for more information about compost: http://www.extension.umn.edu/info-u/plants/BG277.html.

  10. Place edging along the flat vertical bed outline that you made with the flat edge spade. Edging will prevent grass from creeping into your perennial bed, maintaining a clean edge. For edging installation instructions seer edging see Poly Landscape Edging.

  11. Before planting, break up clumps of soil on the surface with a rake. This will produce topsoil with evenly sized soil particles.

  12. You may prefer to prepare a perennial bed in the fall. To prepare a perennial bed in the fall, first follow the groundbreaking directions above. If heavy clay soil is dug and left over winter, the frost and cold will help to beak down the lumps of soil.

  13. Once the bed is dug add a thick layer of compost (minimum 2 inches) to enrich the soil and prevent weeds. You can also add a 2-inch layer of leaves. Maple leaves work best because they curl as they dry, creating a light, fluffy mulch. Oak leaves on the other hand remain flat and mat together, smothering the soil. When spring arrives, check the bed several weeks before you plan to plant. If the leaves have decayed you can go ahead and plant. If they have not yet decayed, rake them off; the soil will be loose, fertile and ready to plant.
Additional Perennial Garden Website Articles:

Explore Cornell - Cornell University
Flowers: Basics
How to Grow Perennials: Introduction to Perennials
How to Grow Perennials: Caring for Perennials

Iowa State University
Digging Smart (proper digging techniques)
This article originally appeared in the March 23, 1994 issue, pp. 28-29.

Neb Guide - Nebraska Cooperative Extension, G87-828-A (Revised April 1999).
Growing Perennials (site analysis, soil preparation, selecting plants and planting, routine maintenance, dividing, insects and disease)

Neb Guide - Nebraska Cooperative Extension, G91-1015-A (Revised April 1999),
Perennials (chart/photos of perennials).


References:

Benjamin, Joan. 1996. Great Gardening Shortcuts, Rodale Press, Emmaus, PA. pp. 326 - 328.

Burrell, C. Colston. 1999. Perennial Combinations, Rodale Press, Emmaus, PA.

Coleman Heller, M. Jane, Decker Hodge, Karla S. 1996. Pictorial Guide to Perennials, Merchants, Kalamazoo, MI.

Cornell University, Expore Cornell. n.a. "Flower Garden Design - Introduction to Color." http://www.explore.cornell.edu/scene.cfm?scene=home%20gardening&stop=
HG%20%2D%20Flower%20Garden%20Design%20%2D%20Color
.

Cornell University, Explore Cornell. n.a. "Flower Garden Design - Texture." http://www.explore.cornell.edu/scene.cfm?scene=home%20gardening&stop=
HG%20%2D%20Flower%20Garden%20Design%20%2D%20Texture
.

Eliason, Roger D. Aug. 15, 1999. "Focus on: the Soil Testing Lab!" Yard & Garden Line News, Vol. 1 Number 9. University of Minnesota Extension Service. http://www.extension.umn.edu/yardandgarden/YGLNews/YGLN-Aug1599.html

Greenwood, Pippa. 1995. The New Gardener, Dorling Kindersley Limited, London. pp. 26-27.

Harper, Pamela J. 1991. Designing with Perennials, Macmillian, New York, NY.

Hanchek, A., Taylor, J.L., Allenstein, P., Cameron, A.C. "Growing Perennials," Michigan State University Extension Service, Extension Bulletin, No. 556

Iowa State University, Department of Horticulture. March 15, 1996. "Garden Color," Horticulture and Home Pest News. Issue IC-475(4). http://www.ipm.iastate.edu/ipm/temp/hort.031596.html#color.

Kaczmarski, Jennifer. n.a. "Amending Soils for Perennial Beds," Sustainable Urban Landscape Information Series (SULIS), University of Minnesota. http://www.sustland.umn.edu/implement/amending_soils.html

MacCaskey, Michael. 1996. "Small is Beautiful," National Gardening Association. http://www.garden.org.

Michigan State University Extension Service, Online Fact Sheet. 11/12/99. "Use of Color," NCR-221. http://www.msue.msu.edu/msue/imp/modzz/00001582.html.

Oster, Maggie. Perennials. National Home Gardening Club, Minnetonka, MN, 1997. pp. 17-19

Remington, Judy, Temenos Garden Services, personal interview, June 2000.

Texas A&M University Extension Service Publications. n.a. "Color Rotation," Plant Answers. http://aggie-horticulture.tamu.edu/PLANTanswers/publications/flowers_all_seasons/color.html.

Von Trapp, Jane. 1999. "Entry Garden Make-Over," National Gardening Association. http://www.garden.org.

Whiting, David. 1995. "Composting, Using It," University of Minnesota Extension Service, Online Fact Sheet 278. http://www.extension.umn.edu/info-u/plants/BG277.html.


This implementation report was developed by Danielle Sanborn and Karyn Vidmar, students, University of Minnesota Department of Horticultural Science.

 
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