Planting in Prepared Beds Herbaceous Plants

When to Plant Annuals  Plant annuals in the spring after the threat of frost has passed.  Around mid-May in our area.

When to Plant Perennials  Spring is ideal because of predictable rains and it marks the start of the growing season.  Summer is acceptable providing you have irrigation.

Planting Perennials in the Fall  Fall is also acceptable. In fact, you can plant right up to the time the ground freezes. Fall planting tips: –If possible, select plants in larger containers. Plants in larger containers have more extensive root systems and have a smaller chance of frost heaving. –Water the plants in after planting. –Provide winter protection in the form of a mulch. Winter mulch application prevents soil freeze/thaw cycles. Use 3-4 inches after the ground has frozen.

Spacing  Annuals –Spacing between plants can vary from inches depending upon the container size and finished size of the plant. –The label that comes with each flat of annuals will provide spacing recommendations.

Spacing  Perennials (DiSabato-Aust, 1998) –less than 12 inches tall8-12 inches –12 to 30 inches tall15-24 inches –greater than 30 inches tall24-36 inches  15 inches seems to be the “average” spacing for perennial plants.

Determining the Number of Plants Required  In order to determine how many plants are needed to fill a bed you need to know… –The area of the planting bed in square feet. –The desired spacing between plants.

Total Bed Area  If the bed is square or rectangular in shape, the total bed area is simply the length x width. 25 ft 15 ft 25 feet x 15 feet = 375 square feet

Total Bed Area  If the bed is triangular shaped, the total bed area is equal to 1/2 (base x height). 20 ft 30 ft 1/2 (20 feet) x 30 feet = 300 square feet

Total Bed Area  If the bed is circular, the total bed area is x radius ft x 12 feet 2 = square feet

Number of Plants Needed  Once the area of the bed has been determined, the next step is to select a suitable spacing.  After a spacing has been selected, use a spacing chart to determine the number of plants needed.

Spacing Chart

Number of Plants Needed  A rectangular bed measures 15 ft. wide by 28 ft. long.  Desire to plant Rose Periwinkle at a 6 inch spacing. How many plants will you need to fill up the bed? Area = 15 ft x 28 ft = 420 square feet At a 6 inch spacing you need 4 plants per sq ft. 420 sq ft x 4 plants per sq ft = 1,680 plants

Planting Depth  For containerized annuals and perennials: –water thoroughly before planting –plant at the same depth at which they were growing in the container

Pot Bound Plants  If the containerized plants are “pot bound” or “root bound”, use pruners to cut the root mass in 3 different places.  The cut roots will form branch roots which will grow out into the bed.

Mulching  Mulching the bed after planting provides the following benefits: –weed control –moisture retention –moderates soil temperature fluctuations –protects against erosion and soil compaction

Mulch Depth  Apply a maximum of 2 inches of mulch to the bed (DiSabato-Aust, 1998).  Avoid applying mulch too heavily around the crowns of the plants.  Applying too much mulch will cause your plants to rot.

Mulching Materials  For annual and perennial beds I recommend using an organic mulch.  There are many materials to choose from: –hulls, cobs, shells –compost –wood chips –bark chips, etc.

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