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March Garden Tips

We’ll soon know if March is going to come in like a lamb and go out like a lion. Time will tell. What I do know is that a few days spent outdoors tending to the following chores will get your garden off to a great start.


  • Set up an outdoor thermometer and a rain gauge. Keep a journal of the weather and when plants start to bloom.
  • Set up and Clean water features and fountains.
  • Get those weeds while they small and easy to control. Pull them by hand or spot kill weeds with a herbicide. Understand that different weeds require different herbicides. Don’t guess which to use. Check to view our Garden Remedies Page and obtain more specifics.
  • If your not an organic gardener consider PREEN (a pre-emergence herbicide) which will prevent new weeds from germinating for up to 3 months. Don't delay; apply it now before new weeds germinate, but be aware it must not be used on garden areas you expect to plant seeds.
  • The heavy Pittsburgh clay soil, that many of us have, is often very wet in March, so check the soil before digging, cultivating, tilling. Walking on wet soil will cause it to compact. So wait until the ground dries before starting to work in your flower and vegetable beds. Simply make a little ball of it in your palm- if it wads up and sticks together it is too wet, if it is still fairly crumbly-you can work the soil.
  • Add amendments to the soil, such as compost, and gypsum to allow for better internal soil drainage. These products make the soil more friable and less compact and promote better plant growth. Raised beds will provide better drainage when one has wet heavy soils. Remember saturated soils result in root diseases for plants not adapted to this condition.
  • Quality soil is the foundation for good plant growth. Test your soil before planting new areas. Soil tests will give you important information like pH, (a scale of soil acidity) organic matter, soluble salts, and major nutrients in soil. Recommendations for amendments will also be provided. A soil test mail packet can be obtained from Penn State Cooperative Extension at 412-473-2540. Once you receive it, follow directions for how to put in the soil and how to fill out the form. Remember when you dig up soil for mailing to let it dry out.


  • Transplant roses, shrubs and ornamental trees before the leaf buds open.
  • Apply the natural slow release Espoma Tree Tone fertilizer to trees & shrubs if growth last year was not as vigorous as desired.
  • Deal with pests now. A lime sulfur spray is organic and protects against scales, mites, and borers on fruit trees, roses, and shrubs as well as black spot and powdery mildew. It's a dormant spray, so apply before your plants begin to bud out. ( it can spot brick, stucco, and leave spots on paint so take care.) An easer to use alternative would be Bonide All Seasons Horticultural Spray Oil. After plants begin to bud, use Bonide Copper Fungicide. Use all compounds cautiously; read and follow manufacturer's instructions.
  • Trim back winter-killed rose canes to one inch below blackened area and all rose canes to about a foot or two above ground level. (This does not apply to climbing roses.) Once buds begin to form cut the stems back to a strong fat bud
  • Before you start pruning a shrub, step back and notice the branch structure and form. First remove weak thin interior branches, branches that cross others, and those that may be growing contrary to the overall shape of the plant. Then to encourage new growth, remove a few of the oldest stems at the plants base.
  • You can prune summer-blooming shrubs such and Rose of Sharon, Spiraea, Potentilla and Summersweet (Clethra). Wait to prune your spring-blooming shrubs (such as forsythia and lilacs) until they've finished blooming so you don't cut off this year's flowers.
  • Now's the time (before it gets too hot and dry) to plant deciduous and evergreen trees and shrubs, weather and soil conditions permitting.
  • Complete the pruning of shrubs, ornamental trees before growth starts, except for spring flowering shrubs. Prune those which bloom in spring as soon as they finish flowering. Trees which bleed such as birch and maple should not be pruned until after their leaves are fully developed.
  • Older flowering shrubs that have grown too tall and are not blooming well can be rejuvenated by using "chain saw pruning," This involves cutting the whole plant down to within 3"- 4" of the ground. It is amazing how fast shrubs will grow back following this severe pruning and they will have much better form and flowers in coming years.


  • It is now the time to plant cool season annuals in the Pittsburgh area if they are properly hardened off. (call for advice) Plants that provide early spring color include pansies, violas, snapdragons, nemesia and alyssum. I highly recommend the new and prolific blooming Osteospermum (African daisy) and Techno Heat Blue Lobelia.
  • Plant sweet peas for wonderful fragrance and cut flowers. Plant sweet peas from the middle to the end of the month. Soak seeds overnight in luke-warm water to promote germination. Provide a trellis or other support for the plants to grow up.
  • All spring bulbs should be up and growing now. When you see the flower stalk emerging from the foliage, it's time to fertilize. Use a complete fertilizer such as Espoma Bulb Tone and or Bone Meal (organic), or Espoma Garden Food 5-10-5.
  • Plant spring flowering annuals like forget-me-nots, dianthus, English Daisy, Sweet William, and viola


  • Cut back remaining dead stems of any perennials or grasses before or as the plants put out new growth. Here's a hint: Cut dead stems back to 3 or 4 inches tall. This will help you remember where late-emerging varieties such as perennial hibiscus and butterfly weed are planted. Clematis in Group 2 bloom in late spring or early summer, then again sporadically, on new shoots and old stems. These should be pruned in March before new growth begins.
  • Group 2 Clematis are those that bloom mostly on new shoots, and therefore normally bloom in late spring or early summer. Vines of this group require a bit more pruning finesse than do the other Clematis groups. If you cut back these types drastically right after the first bloom, they will not bloom again later in the summer. If you cut back drastically just before growth begins, you will have removed most of the flower buds of the spring flush.
    The recommended way to prune Group 2 is to lightly thin out and disentangle stems before growth begins in late winter or early spring, and then go over the plant again after the earliest flowers fade in late spring or early summer, severely shortening the stems that bore those flowers. If the plant tends to bloom more heavily later rather than earlier in the season, you can be more heavy-handed when thinning stems before growth begins in early spring.
    Group 2 Clematis include most of the Large-flowered hybrid cultivars, such as: 'Barbara Jackman', 'Bees Jubilee', 'Belle of Woking', 'Beauty of Worcester', 'Doctor Ruppel,' 'Duchess of Edinburgh', 'Elsa Spath', 'General Sikorski', 'Henryi', 'Jackmanii', 'Nelly Moser', 'Niobe', 'Royal Velvet', 'The President', 'Snow Queen', 'Will, Goodwin', 'William Kennett', 'William Pennell' and others. For a complete list of Group 2 Clematis go to: http://www.gardenforumhorticulture.co.uk/clematis-pruning-list.htm.
  • As temperatures begin to warm, and plants emerge from dormancy, slowly remove protective mulches. Beware of removing mulches too soon since hard freezes are still possible
  • Apply the natural slow release Espoma Plant Tone fertilizer around perennials when new spring growth is visible.
  • Most perennials bloom only for a 2 to 4 week period. So when adding new perennials to your garden, consider those that retain great foliage throughout the season. Also seek varieties that re-bloom or have extended the flowering periods. Be sure to choose a mix of early, mid and late blooming varieties.
  • Feed peonies with Espoma Plant Tone when they are about 2 - 3 inches tall. Put peony supports in place. The round wire basket-weave types are best.
  • Early spring is also a good time to divide and transplant summer blooming perennials such as hosta and sedum. Divide as they start to emerge from the soil. Most perennials do best when divided every three years or so, but some vigorous growers could use splitting every two or three years.
  • Here's a hint: It's best to wait and divide many spring-blooming favorites such as bleeding heart and barrenwort after they've finished blooming. You’ll want to hold off dividing your peonies, iris, and poppy until late August here in the Pittsburgh area.
  • Bluebells are superb for naturalizing in the same manner as daffodils but prefer a shadier location, and will bloom even where they get no direct sun at all


  • St. Patrick's Day is the traditional time to plant peas and potatoes. Rhubarb, asparagus, radishes, lettuce, broccoli, and cauliflower and onion sets can also be planted as soon as the soil is workable. While you're out planting, add some pansies to your spring vegetable garden. They'll add color, and you can use the cheery blooms in salads.
  • Plant parsley in your herb garden


  • Spray fruit trees, berry bushes and canes with Bonide Lime Sulfur Spray. It is organic and protects against scales, mites, and borers. It's a dormant spray, so apply before your plants begin to bud out. (Protect your house; it can spot brick, stucco, and leave spots on paint.) Use all spray compounds cautiously; read and follow manufacturer's instructions.
  • If you haven't already done so, now's a great time to prune fruit trees (including apples, pears, and cherries) and fruits such as raspberries and grapes.
  • http://extension.psu.edu/gardening/fphg PSU Extension link to 'Fruit Production for the Home Gardener'


  • To repair bare spots in lawns combine 5 shovels of sand, 1 shovel of topsoil, 1 shovel of grass seed and 1 cup of Master SR4 Slow Release fertilizer. Treat bare spots with this mixture, cover with straw, and water often so that the soil remains moist. Do this until the grass is growing strong.
  • Even though your grass may be starting to green up, it's probably too early to fertilize. Wait a month or so until your grass is actively growing before feeding it.
  • Crabgrass will begin to germinate when the soil temperature reaches 50 degrees F So, watch the forsythias and when they bloom apply a crabgrass pre-emergent herbicide to your lawn. Hold the fertilizer until after the first mowing.


  • As the days grow longer, and sunlight gets stronger you'll probably start to see new growth on your houseplants. You can typically start watering them a little more and feeding them this month with Bonide Liquid Plant Food on a regular basis to help them push new growth.
  • Repot those that are root bound. For step by step directions Read How To Repot.
  • Avoid over-watering as weakened plants are more readily subject to disease and root rot.
  • If you want flowers on your cactus, plant it in a small pot. Most cacti bloom sooner if root bound.

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