April gardening tips from master gardener

1. Tomato seeds may be started indoors any time now.

2. Roses, hydrangeas and any other covered plants may be uncovered mid-April.

3. Still time to use dormant oil (Temp Plus Zero, early AM, no precip. for 24hr.s.) .

4. CLEMATIS: As soon as clematis are showing some green, mulch with compost.

When buds start to form on clematis, give them a dose of rose fertilizer and a handful of Epsom salts.

5. ROSES: May be pruned if no heavy frosts are forecast and forsythia is blooming in your vicinity. Prune back to 10”-12” to an outward facing bud. Cut out any branches smaller than a pencil width, and diseased, broken or crossing branches.  Prune only diseased, broken or dead branches on climbing roses.

6. LAWNS. Avoid walking on lawns if they are still damp as this compacts the soil.

Rolling lawns should be avoided unless extreme upheaval has occurred

Aerating is only necessary if there is a heavy layer of thatch. A small amount of thatch will actually decompose, adding nutrients into the lawn, and allowing the worms to aerate your lawn as they consume the thatch.

Lightly raking lawns fluffs up lawns and helps prevent early fungal diseases.

Lawns may be over seeded as soon as soil thaws (Clover is a good choice as it provides its own nitrogen, is avoided by chinch bug, is more drought resistant because of its deep roots, and provides flowers for pollinators.

If you choose to fertilize your lawn (not necessary if fertilized in fall), the best choice is compost or slow release (Organic) fertilizer. Holding off till May gives the lawn a chance to use up stored supplies from last year saving you time and money. If crab grass was a problem last year, try corn gluten (a pre-emergent). Do not use if reseeding the lawn. Pre-emergent  (for weeds and crab grass seeds) may be applied around the time mock orange blooms.

7. Prune back spiarea (not Bridal Wreath) drastically to prevent bare leggy plants.

8. Time to put out birdbaths and hummingbird feeders. Use a sugar solution of 4 cups water to 1 cup sugar, bring to a boil. Keep extra in sealed jar in refrigerator.  DO NOT use food color or honey.

9. If not already done, prune hydrangeas, (paniculata and aborescens) fall flowering clematis, butterfly bushes (to  6 inches) ninebark or any other summer flowering shrubs.

10. If compost bin wasn’t utilized in the winter, now is a good time to start it. If you didn’t save some leaves from last fall you may use last years dead, dry plant growth (chopped into small pieces), or shredded Newspaper for the “brown” layer

11. If necessary delphiniums are best divided as soon as shoots start to show..

12. Radish, parsley, beets, chard, peas and onion seeds may be planted as soon as soil dries out. To test grab a handful, if it balls up and stays that way, it’s still too wet.

13. If dividing snowdrops, do it with leaves still green.

14. When cutting back grasses, cut just above the new green tips to avoid blunt ends.

15. When peony tips emerge, add well-rotted manure or compost.

16. Time to divide any perennials with dead center areas.

17. If perennials crowns have heaved and are exposed, press down or mound up.

18. Best time to move shrubs is before leaf buds open.

Julia Kron is a member of the Fergus and Distruct Horticultural Society and a Guelph-Wellington County Master Gardener.