This gardening to-do list is focused on zone 8, but it should also be somewhat germane for zones 7 and 9. (The photo above is of a peach blossom)
Plant fruit trees and shrubs - bare-rooted plants should be planted by the end of the first half of the month. Potted plants can be planted the entire month.
Plant trees and shrubs that are potted.
Fruit trees can be pruned before the buds begin to bloom (wait until after fruiting for the fruit bushes)
You are running out of time to prune shade and ornamental trees. Ideally, pruning should be completed before the trees and bushes start to leaf out.
Clear out dead foliage of last year's perennials such as turk's cap. I do not cut back the bare stems of hydrangeas.
Spring flowering plants can be pruned after they finish blooming, e.g. carolina jessamine, wisteria, lady banksia roses, spirea, forsythia, flowering quince.
Continue vegetable seeds and transplant per the following schedule - Planting Schedule. Finish cool season vegetable plantings. You can begin planting warm season vegetables after the last frost date, which is approximately March 20th in Dallas. Visit the following site for last frost dates - Interactive Map. You will want to wait until the soil warms up further for some vegetables like sweet corn and peppers.
If you did not fertilize in February, fertilize lawn and beds with organic fertilizer.
If you did not do so in February, add compost and topdress mulch.
After the last frost date, begin spraying fruit and vegetables with compost tea or Garrett Juice mixture. I try to spray every other week with a backpack sprayer, but it is not necessary to spray this frequently. (This year, I am going to experiment with a mixture including Garrett Juice, Seaweed extract, Bt additive (for caterpillers and pests), garlic juice (insects), and actinovate (prevent fireblight and other fungus) -- I'll report back as to how it does).
In the first part of March, spread diatomaceous earth around your strawberry plants to deter slugs and pill bugs.
You can continue to plant cold weather annuals - e.g. petunias, pansies, pinks, alyssum, etc. After the last frost date, you can begin planting warm weather annuals.
Even after the average last frost date, keep an eye on the forecast for any unexpected late freezes. Be prepared to water your tender, warm weather transplants before the frost hits. Be prepared to cover those tender transplants with frost cloth or some other type of covering.
After the last frost date, begin sowing beneficial insects if you do not have an existing, abundant population. Ladybugs, green lacewings, praying mantids, trichogramma wasps, beneficial nematodes, etc.
Prepare for the birds. Get your Eastern Screech Owl and Barn Owl houses up. Put out the goldfinch feeders with thistle. At the end of March, get your hummingbird feeders out in case there are any early visitors. Get your purple martin house up and ready for the scouts.
Cut back and trim groundcover in the first part of the month, if necessary.
Late March is a good time to put down sod.
Water as needed. March is the rainy season, so only infrequent watering should be necessary.
** The Organic Manual, Howard Garrett (Tapestry Press 2002).