Gardening by Month - March
Monthly Tips and Tasks

Category
 
Week
 
Activity 
  1 2 3 4  
 Houseplants x x x x Two handsome houseplants that provide fragrant blossoms indoors this month are the Confederate jasmine (Trachelospermum jasminoides) and Japanese pittosporum (Pittosporum tobira). Both thrive in average home conditions and are easy plants to grow.
  x x x x As day lengths increase, plants begin new growth. Repot rootbound plants, moving them to containers 2 inches larger in diameter than their current pot. Check for insect activity and apply controls as needed. Leggy plants may be pruned now.
 Ornamentals     x x x x Trees, shrubs and perennials may be planted as soon as they become available at local nurseries.
  x x x x To control iris borer, clean up and destroy the old foliage before new growth begins.
  x x x x Fertilize bulbs with a "bulb booster" formulation broadcast over the planting beds. Hose off any granules that stick to the foliage.
  x x x x Dormant mail order plants should be unwrapped immediately. Keep the roots from drying out, store in a cool protected spot, and plant as soon as conditions allow.
  x x x x Loosen winter mulches from perennials cautiously. Re-cover plants at night if frost returns. Clean up beds by removing all weeds and dead foliage at this time.
  x x     Heavy pruning of trees should be complete before growth occurs. Trees should not be pruned while the new leaves are growing.
  x x     Seeds of hardy annuals such as larkspur, bachelor's buttons, Shirley and California poppies should be direct sown in the garden now.
    x x x Summer and fall blooming perennials should be divided in spring.
      x x Ornamental grasses should be cut to the ground just as the new growth begins.
      x x Spring bedding plants, such as pansies and toadflax (Linaria sp.), may be planted outdoors now.
      x x Apply a balanced fertilizer such as 6-12-12 to perennial beds when new growth appears.
      x x Apply sulfur to the soils around acid-loving plants such as azaleas, rhododendrons, hollies and dogwoods. Use a granular formulation at the rate of 1/2 pound per 100 square feet.
        x Gradually start to pull back mulch from rose bushes.
 Lawns x x x x Mow lawns low to remove old growth before new growth begins.
    x x x Apply broadleaf herbicides now for control of cool-season perennial and annual weeds. These must not be applied to areas that will be seeded soon.
    x     Apply controls for wild garlic. It will take several years of annual applications for complete control.
      x x Thin spots and bare patches in the lawn can be overseeded now.
 Vegetables x x x x Any root crops such as horseradish, parsnips, Jerusalem artichokes, or carrots still in the ground from last year should be harvested before new green top growth appears.
  x x x x Cultivate weeds and remove the old, dead stalks of last year's growth from the asparagus bed before the new spears emerge.
  x x x x Fertilize the garden as the soil is being prepared for planting. Unless directed otherwise by a soil test, 1 to 2 pounds of 12-12-12 or an equivalent fertilizer per 100 square feet is usually sufficient.
  x x     Delay planting if the garden soil is too wet. When a ball of soil crumbles easily after being squeezed together in your hand, it is dry enough to be safely worked.
  x x     Asparagus and rhubarb roots should be planted as soon as the ground can be worked.
    x x x Plant peas, lettuce, radishes, kohlrabi, mustard greens, collards, turnips, Irish potatoes, spinach and onions (seeds and sets) outdoors.
      x x Plant beets, carrots, parsley and parsnip seeds outdoors.
      x x Set out broccoli, cabbage, Brussels sprouts, Chinese cabbage and cauliflower transplants into the garden.
        x Start seeds of tomatoes, peppers and eggplants indoors.
 Fruits     x x x x Gradually remove mulch from strawberries as the weather begins to warm.
  x x x   Continue pruning apple trees. Burn or destroy all prunings to minimize insect or disease occurrence.
  x x     Continue pruning grapes. Bleeding causes no injury to the vines. Tie vines to the trellis before the buds swell to prevent bud injury and crop loss.
    x     Cleft and splice grafting can be done now. This must be completed before rootstocks break dormancy.
      x x Aphids begin to hatch on fruit trees as the buds begin to open.
      x x Apply dormant oil sprays now. Choose a dry day when freezing temperatures are not expected.
      x x Spray peach trees with a fungicide for the control of peach leaf curl disease.
        x Mulch all bramble fruits for weed control.
        x Peaches and nectarines should be pruned just before they bloom.
 Miscellaneous     x       Red maples begin to bloom.
  x       Set up nesting boxes for bluebirds.
  x       Watch for the harbinger of spring (Erigenia bulbosa) blooming in rich wooded areas.
    x x x Spicebush is blooming in moist woodlands.
    x     Raise purple martin houses this week.
      x   Purple martins return to the St. Louis area.
         x The white flowers of serviceberry (Amelanchier sp.) and wild plum (Prunus americana) are showy in wooded areas.
        x Watch for the fuzzy blooms of the pussy willow (Salix sp.).
March Pests and Problems


Spray to control lawn weeds such as chickweed and dandelion now when they are growing actively.
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Winter Annual Weeds
Common chickweed (Stellaria media)--also called, Alsine media, starwort, starweed, bindweed, winterweed, satin flower, tongue-grass--can be a pest of the lawn or garden 
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Winter Annual Weeds
Henbit (Lamium amplexicaule)--also called, dead nettle, blind nettle, bee nettle--can be a pest of the lawn or garden 
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Perennial Broadleaf Weeds in Lawns
Dandelion in bloom, a common perennial weed in lawns and gardens 

Apply crabgrass preventor between mid-March to mid-April or about the time forsythia is blooming. If you decide to use a weed and feed product, do not use a fertilizer high in nitrogen.
 
 
 

If not already done, remove and dispose of the foliage of plants such as roses, peonies, iris, daylilies, apples, and horsechestnut, which are subject to annual fungal leaf diseases.
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Black Spot of Rose
Yellowing rose (Rosa) leaves with black spots are characteristic of black spot of rose 
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Peony Blotch
Peony blotch on peony (Paeonia
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Leaf Spot Diseases of Shade Trees and Ornamentals
Unidentified fungal leaf spot on pin oak (Quercus palustris); note progression of spots from blotch to blight (from left to right) 

Scout for and remove tent caterpillar webs.
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Eastern Tent Caterpillar
Eastern tent caterpillars (Lepidoptera) in web feeding on apple (Malus); note that the webs are in branch crotches 
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Eastern Tent Caterpillar
Close-up of egg mass of eastern tent caterpillar (Lepidoptera) on flowering quince (Chaenomeles
 

Frost is possible this month. Do not uncover plants or plant tender plants too early. Little can be done to protect large trees and shrubs but you may be able to give some protection to small plants closer to the ground.

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Winter Injury: Frost Injury, Ice Damage
This breathable fabric draped around a pot shows one method of protecting tender plants when frost is predicted 
 
 

Apples, pears, and other plants infected with fireblight should have had diseaed wood pruned out by the end of February. If this was not completed by then, wait until dry weather in mid summer. Pruning wounds made at this time of year may provide entry points for the bacteria that caused the disease.
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Fireblight
Fireblight canker and twig dieback on crabapple (Malus
 
 

Don't forget to inspect plants you are overwintering indoors for insects. Insect populations can increase rapidly at this time of year before the plants are set outside for the summer.
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Scale Insects - Indoors
Close-up of scale (Hemiptera) on frond of kentia palm (Howia
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Mealybug - Indoors
Mealybug (Hemiptera) colony on coleus (Solenostemon
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Spider Mites - Indoors
Close-up of two-spotted spider mite (Acari) on angel's trumpet (Brugmansia); includes adults, immatures and eggs 

Cool-season grasses are best fertilized in fall. If you do apply fertilizer in spring, make sure it is low in nitrogen. Nitrogen applied in spring encourages excess growth, which is more susceptible to disease. Hold off until May to fertilize zoysia or other warm-season grasses.
 
 
 

Do not apply dormant oil sprays to a plant after its buds have begun to swell as damage may occur.
 
 
 

Do not work wet soils.
 
 
 

Observe indoor seedling closely for signs of damping off. Treat if necessary.
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Damping-off
Damping-off of snapdragon seedlings (Antirrhinum) caused by Rhizoctonia sp. Note constriction of stems at the soil line. R. K. Jones, NCSU, Bugwood.org