Half of your success in gardening in Texas will be in doing the right things. The other half will be in doing them at the proper times.
This is an abbreviated gardening calendar, updated for 2017, that highlights the most critical, time-sensitive things you’ll need to do each month of the year. It begins with April, and runs through the end of the year and into early next year.
Plant: Top things to plant in early to mid-April include full-sun annuals: moss rose, purslane, trailing lantanas, pentas, Dahlberg daisy, cosmos, celosias, small-flowering zinnias, marigolds, firebush, copper plant, cleome, purple fountain grass, ornamental sweet potatoes and amaranthus. Shade annuals including coleus, impatiens, nicotiana, caladiums, elephant ears, begonias. Warm-season vegetables: tomatoes, peppers, beans, squash, melons, corn and cucumbers, followed a couple of weeks later by eggplant, okra, southern peas and sweet potatoes.
Prune: Spring-blooming shrubs and vines as needed to shape, immediately after they finish flowering. Mow grass at the recommended height to keep it low and dense.
Fertilize: Lawns and landscape plants, as well as vegetables to promote vigorous growth. Soil tests usually suggest all-nitrogen plant foods for clay soils, and high-nitrogen (4-1-2 ratio, for example) for sandy soils. Half or more of the nitrogen should be in a slow-release form.
On the lookout: Lawns for broadleafed weeds (clover, dandelions, dichondra and others). Apply broadleafed weedkiller spray containing 2,4-D. Thrips may cause rose buds to singe around petals’ edges and fail to open. Systemic rose insecticide will prevent or eliminate, but it will take two or three weeks. Broccoli, cabbage leaves that have been riddled by cabbage loopers. Control with Bacillus thuringiensis biological worm spray or dust.
Plant: Warm-season annuals to replace winter color that is wearing out. The best choices include trailing lantana, firebush, gomphrena, cosmos, Dahlberg daisy, moss rose, hybrid purslane, pentas, copper plant, purple fountain grass. Use caladiums, coleus, impatiens, begonias in shadier spots. Tropical annuals hold up to summer’s heat well, including tropical hibiscus, pentas, crotons, Mexican heather, bougainvilleas, dipladenia, African bush daisy and esperanza. Start new St. Augustine, Bermuda and other warm-season turf grasses. Keep new grass moist until it has established deep roots.
Prune: Spring-flowering shrubs and vines now that they have finished flowering. Climbing roses, after major spring bloom. Errant growth from evergreen shrubs and vines, to maintain good shape. Avoid formal shearing.
Fertilize: Turf requires superior quality all-nitrogen (clay soils) or high-nitrogen (sandy soils) fertilizer unless a recent soil test suggests otherwise. Use the same type of high-nitrogen fertilizer for ground covers, shrubs, trees and even flower and vegetable beds. Container plants with high-nitrogen, water-soluble fertilizer with each watering.
On the lookout: Powdery mildew on new growth, buds of crape myrtles, zinnias, euonymus resemble dusting of flour. Keep foliage dry, and apply labeled fungicide. Continue black-spot protection program for roses with labeled fungicide. Broadleafed weedkillers to eliminate nongrassy weeds in any turf. Follow label directions implicitly to avoid damage to desirable trees, shrubs. Use Image or Sedgehammer to eliminate nutsedge in St. Augustine or Bermuda turf.
Plant: Warm-season turf, early in month. Assuming water curtailments allow, water lightly and at least once or twice a day for 1-2 weeks, until roots become well-established. Crape myrtles, while in full bloom, to ensure colors. Heat-tolerant annuals, including moss rose, purslane, trailing lantana, pentas, copper plant, firebush, purple fountain grass, caladiums, coleus, crotons, tropical hibiscus, mandevilla and Gold Star esperanza.
Prune: Erratic spring growth from shrubs, trees and ground covers. Avoid formal shearing. Mow frequently (four- or five-day intervals) to keep turf low, dense. Allowing grass to grow tall weakens it and does not improve its drought tolerance.
Fertilize: Turf, shrubs, trees, ground covers, flowers and vegetables with all-nitrogen fertilizer in clay soils, high-nitrogen fertilizer in sandy soils. Patio pots and hanging baskets with high-nitrogen, water-soluble food every few times that you water them. Apply iron/sulfur amendments to correct iron chlorosis (yellowed leaves, dark green veins; most prominent on newest growth first). Keep iron additives off masonry, painted surfaces.
On the lookout: Webworms in pecans, walnuts, persimmons and other trees. Remove with pole-pruner as soon as you see webs starting to form. Bagworms devouring foliage of junipers, arborvitae, cypress and other conifers (Bt or general-purpose insecticide). Tomatoes may show lower leaves first bright yellow, then dried and crisp. This is early blight — control with labeled fungicide. Spider mites may cause leaves of beans, tomatoes, marigolds, violets and many other plants to turn tan and crisp.
Plant: Fall tomatoes. Best varieties are small and mid-size types. Protect new transplants from afternoon sun for three or four days at the outset. Warm-season turf from sod or plugs or by seeding. Crape myrtles. Choose while in bloom to ensure proper colors. Plant at once, and hand-water every day or two through the rest of the summer.
Prune: Roses monthly to maintain shape, vigor. Remove any showing rose rosette virus symptoms. Summer perennials to remove old flower stalks and seed heads. Routine shaping of landscape shrubs, vines and ground covers — avoid formal shearing.
Fertilize: Lawn grasses every eight to 10 weeks with high-quality, slow-release high-nitrogen (sandy soils) or all-nitrogen (clay soils) fertilizer. Wait until September to feed St. Augustine again, to lessen chance of gray leaf spot. Container plants with each watering (perhaps as often as daily in the heat) with very diluted, water-soluble fertilizer.
On the lookout: Aphids causing sticky honeydew drippage from pecans, oaks, crape myrtles and other trees. Leafrollers in vinca, sweetgums, cannas and others (systemic insecticide). Chinch bugs in hot, sunny parts of St. Augustine turf. Grass will appear dry even after watering. Apply approved turf insecticide. (Imidacloprid is a standard.)
Plant: Fall vegetables: beans, cucumbers, squash from seeds on first week of August, followed by transplants of cabbage, broccoli, cauliflower, and Brussels sprouts and leafy and root crops from seed. Fall annual color from vigorous 4-inch potted transplants. Fall-flowering perennials and fall-flowering bulbs as they become available in local retail nurseries.
Prune: Bush roses early. Trim by one-third (less severe than the mid-February pruning) to encourage new fall growth and bloom. Remove erratic growth from shrubs, but save major pruning for late winter.
Fertilize: Container plants, including patio pots and hanging baskets with water-soluble, high-nitrogen plant food. Daily waterings quickly leach nutrients out of the soil. It might be wise to postpone other normal August feedings into early September, when more favorable conditions will return.
On the lookout: Brown margins on leaves of plants usually indicate moisture stress, such as plants getting too dry, too much sun, too much fertilizer, or trunk or root damage. Pecans should be protected from hickory shuckworms and pecan weevils by an early-August application of Malathion, but only if a crop of pecans is expected. Repeat the application in late August.
Prune webworms out of pecans, walnuts, persimmon and other host trees as they appear. Long-handled pole pruners work best. Sprays are difficult to apply and, therefore, not highly effective.
Plant: Finish wildflower seedings this month. Plant them into tilled soil, away from competition of turf grasses. Finish planting St. Augustine sod by mid-month to allow time for deep root growth before the first freeze. Bermuda seed should also be sown no later than mid-September, but sod can be planted later in month.
Prune: Tidy up perennial beds by removing spent flowers, seed heads and old foliage now. Root-prune trees and shrubs you intend to move this winter, also wisterias that have failed to bloom normally in past springs. Remove large surface tree roots that threaten damage to pavement should they be left in place.
Fertilize: Lawn grasses and landscape and garden plants. Apply a superior quality, high-nitrogen or all-nitrogen fertilizer, then water deeply.
On the lookout: Apply a pre-emergent herbicide such as Halts or Dimension early in September to prevent winter grassy weeds such as annual bluegrass, rescuegrass and rye. (Don’t use if you’re over-seeding your turf.) Gallery products prevent annual broadleafed weeds. Both pre-emergents need to be applied before the weeds sprout and start growing. You can apply them on the same day, then water them both onto the soil’s surface at the same time, but do not try to mix them in the fertilizer spreader. Make two separate passes across the lawn.
Plant: Daffodils, narcissus and jonquils soon after you buy them. Small- and early-flowering types have the best chance of repeating year after year. Tulips and hyacinths must be refrigerated at least 45 days at 45 degrees prior to planting (plant no earlier than mid-December). Dig and divide established clumps of spring- and summer-flowering perennials early in the month. Pansies once temperatures are in the low 80s during the day.
This is the best time to plant shrubs, trees and other landscape plants, so they will have maximum time to establish roots.
Prune: Keep mowing turf at recommended heights right up to first freeze. Remove dead leaves, flower stalks and seed heads from perennial plantings. Remove dead and damaged limbs from trees while you can distinguish them from healthy growth.
Fertilize: Get pansies, other annuals off to a quick start with water-soluble, high-nitrogen food every few days after planting. Last feeding of Bermuda, St. Augustine lawns, trees, shrubs and ground covers should be made very early in the month. This “winterizer” fertilizer should be with the same material you’ve used the rest of the growing season.
On the lookout: St. Augustine will probably develop brown patch, especially if fall rains come. Control with turf fungicide, and cease evening waterings, since they spread the fungus. Watch patio plants for insect, mite and disease problems. Treat as needed before bringing them indoors. Apply glyphosate-type weedkiller early this month to eliminate established grass and weeds prior to rototilling for new garden beds.
Plant: Cool-season annual color, including pansies, snapdragons, pinks, flowering cabbage and flowering kale. Daffodils, narcissus and jonquils, also grape hyacinths, directly into soil. Tulips and Dutch hyacinths should be refrigerated at 45 degrees until Christmas. Wait until first freeze to transplant established trees and shrubs.
Prune: Remove dead and damaged limbs from trees and shrubs, and cable tree limbs that might break during winter ice and windstorms. Tidy up all perennial plantings to remove dead leaves, stem stubble, old seed stalks and other debris.
Fertilize: Annual color plants with high-nitrogen, water-soluble fertilizer with each watering.
On the lookout: Apply broadleafed weedkiller spray (containing 2,4-D) to kill henbit, chickweed, dandelions and clover by Thanksgiving. Protect plants from early frosts and light freezes.
Plant: Spring annual color from 4-inch and larger pots. Finish planting spring bulbs. Plant pre-chilled tulips and hyacinths as soon as soil temperatures are in the low 50s for several consecutive days. Established landscape or native trees and shrubs can be moved after the first hard freeze.
Prune: Trees, shrubs to tidy their growth, also to remove damaged or errant branches. Do not “top” crape myrtles or other shade trees. Fruit trees this winter to establish the “scaffold” branching structure with peaches, plums. Apples will require only the removal of vertical shoots, and pears and pecans will require little regular pruning. Prune grapes back by 80 to 85 percent.
Fertilize: Use a water-soluble, high-nitrogen fertilizer for cool-season color plants, while they’re still growing actively. Apply liquid, high-phosphate, root-stimulator fertilizer to all newly transplanted trees, shrubs.
On the lookout: Prepare to cover pansies, tender shrubs and other plants that could be killed by cold spells. Lightweight landscape fabrics can offer many degrees’ protection. Have the covers on hand, pre-cut to fit each of your beds. Weight them down with bricks or rocks. Disconnect water hoses during freezes.
Plant: New fruit, pecan trees, blackberries and grapes — choose only varieties recommended for your county. Transplanting of native or established trees, shrubs should be done. English peas, asparagus roots late in the month.
Prune: Shade trees as needed to shape or remove damaged branches, also to remove lower branches for better sun penetration to turf. Do not “top” trees. Peach and plum trees to encourage spreading growth with bowl-shaped branching structure. Grapes to remove as much as 85 percent of cane growth. Evergreen shrubs as needed to maintain natural shape. Summer-flowering shrubs, vines.
Fertilize: Root-stimulator fertilizer monthly to newly transplanted trees and shrubs. Cool-season annuals with diluted high-nitrogen, water-soluble plant food each time you water them.
On the lookout: Apply horticultural oil to eliminate scale insects from trees, shrubs. Apply broadleafed weedkiller during period of dry, warm weather to eliminate existing non-grassy weeds.
Plant: Fruit and pecan trees, bramble berries, grapevines early. Cold-hardy vegetables, including onions, English peas, cole crops, leafy and root vegetables. Cold-hardy annual flowers, including pansies, pinks, snapdragons early in the month; then later, calendulas, poppies, alyssum, wallflowers, petunias, stocks, English daisies. Divide established clumps of summer- and fall-flowering perennials. Move shrubs and trees while they are still dormant.
Prune: Summer-flowering shrubs and vines, also shade trees. Never “top” trees. Fruit trees, before growth resumes for spring. Pruning of peach and plum trees is especially important — remove vertical shoots and encourage horizontal branching. Grapes to remove as much as 85 percent of cane growth from each vine. Bush-type roses to half their original heights. (Prune climbing roses immediately after they bloom.) “Scalp” lawn to remove winter-killed stubble and many cool-season weeds.
Fertilize: Asparagus with high-nitrogen fertilizer early in the month. Ryegrass and fescue with high-quality, all-nitrogen fertilizer mid-month. Newly transplanted trees, shrubs with high-phosphate, root-stimulator fertilizer.
On the lookout: Clover, dandelions, henbit. (Broadleafed weedkillers will control any nongrassy weed. Apply during warm, dry spells.) Dormant horticultural oil sprays before buds start to swell late this month, to stop spread of scale insects. Begin fruit spray schedule as buds are fully swollen and showing color, but before they start to open.
Plant: Cool-season annual flowers early in month, including petunias, pansies, snapdragons, calendulas, stocks and sweet alyssum. Finish planting cool-season vegetables early in the month. Nurseries will begin stocking their widest selections of trees, shrubs, vines and ground covers. Choose flowering types such as azaleas, forsythia and quince.
Prune: Reshape spring-blooming vines, shrubs after they finish flowering. Clean up perennial gardens immediately, to remove old stubble before spring growth begins. Thin any new balled-and-burlapped plants by 30 percent, bare-rooted by 40 to 50 percent.
Fertilize: Apply high-nitrogen or all-nitrogen lawn fertilizer to cool-season turf early, warm-season grasses very late in the month. Use same lawn-type fertilizer for shade trees, evergreen and summer-flowering shrubs, ground covers, as well as for spring-flowering shrubs and vines after they have finished blooming.
On the lookout: Apply pre-emergent weedkillers for crabgrass and grassburs. Apply broadleafed weedkiller spray (containing 2,4-D) to nongrassy plants.