gardener's charts
JANUARY | FEBRUARY | MARCH | APRIL | MAY | JUNE
JULY | AUGUST | SEPTEMBER | OCTOBER | NOVEMBER | DECEMBER
written by Scott Millard
Click here for a directory of the year-long garden charts
APRIL
PLANTING
Heat-loving summer vegetables - peppers, eggplants, summer squash, and tomatoes - can go into the garden once soil temperatures reach 60°. Consider mixing in a few culinary herbs. April always seems to have one last frost up her sleeve, so keep materials handy for cold protection.
Plant citrus from containers once the threat of frost has passed. It is important to set the root ball so that the soil level is the same as it was in the container.
Bermuda grass needs heat to establish. By mid-month, if the weather has been warm, plant hybrid Bermuda grass from sod or plugs (hybrid Bermuda grass seed is sterile).
WATERING
Reset your irrigation system timer for longer, more frequent irrigations in late April to accommodate warmer temperatures. For new plants set out this spring, check the soil for moisture every few days. Check fall-planted plants weekly, and water before plants show signs of stress.
CARE
Pests and diseases: Squash vine borers find squash plants as they begin to fruit. Sudden wilting of the vine is a sign of infestation. Examine stems for inch-long white grubs and destroy them.
Fruit trees: If deciduous trees have set a good fruit crop, thin the small fruit so those remaining will reach a good eating size.
Lawns: Bermuda grass lawns awaken from their dormancy this month. Tidy them up with a quick mow and rake. If thatch has built up, dethatch by renting a machine. Water, fertilize with ammonium sulfate, and then water again to set the stage for the greening and growth surge.
MAY
PLANTING
Remove tired petunias, violas, and pansies (cool-season annuals) and replace with their warm-season cousins—periwinkle, zinnias, portulaca, red and blue salvia, and marigolds. Renew the soil in beds and containers before planting by adding organic amendments and ammonium sulfate at the rate of one pound for every 100 square feet. Set out seedlings of warm-season veggies—eggplant, squash, peppers, and melons. Even if you planted some of these in late April, succession planting will stretch out your harvests.
WATERING
As mentioned, watering is the primary gardening activity for the next several months. Check the soil for moisture before plants show signs of needing water. Fruit-producing plants such as peach trees, citrus, and grapevines should receive regular waterings or plants may drop flowers and developing fruit.
CARE
Mulch: Mulch is a material applied in a layer over the root area of plants. A few inches of mulch help cool the soil and reduce evaporation. A layer of almost anything helps, including gravel or stones, but organic mulches such as compost, ground bark products, and lawn clippings also decompose to improve the soil.
Insect pests: Populations of insect pests explode as temperatures warm and as plants produce tender new growth. Spider mites thrive on the undersides of leaves, sucking plant juices. Stippled, yellowing leaves and spiderlike webbing are telltale signs. Wash leaves clean with water and spray infested areas with insecticidal soap.
Protection: Birds and other animals may enjoy your harvests before you can if you fail to protect your plants. Cover fruit trees entirely with netting. A sturdy PVC-pipe framework, staked to the ground and covered completely with wire or netting, will keep most small animals out of vegetable plots. The sun can also be a villain, burning ripening tomatoes and peppers. Cover developing fruits with row-cover materials available at many nurseries.
Fertilizing: If leaves of citrus plants are pale green, fertilize late in May with a complete citrus food. Likewise, fertilize and water roses well. Warm May temperatures bring Bermuda grass out of dormancy. Feed with complete lawn fertilizer or ammonium sulfate.
JUNE
PLANTING
In June, temperatures begin to soar, so consider holding off major plantings of trees, shrubs, and perennials until September or October.
Palms: The grasslike roots of palms establish best with heat, so June and July are good months to plant new palms from containers, or to transplant existing young palms. Wait until soil temperatures warm to at least 75°. Water carefully after planting, and mulch soil to conserve moisture.
Vegetables: Continue succession planting of warm-season vegetables every 3 weeks or so to extend harvests. Sow seeds of squash and melons directly in the garden—the warm summer soil causes seeds to germinate rapidly.
WATERING
The high temperatures and low humidity typical of June weather can quickly stress plants. A daily watering patrol (morning is best) around the landscape helps you spot thirsty plants.
CARE
Prevent weed seeds from germinating. Apply a pre-emergent spray in mid- to-late June before July's summer rains kick off the summer weed crop.
JULY
WATERING
Typically, from the first part of July until late September, some areas of Tucson are blessed with rains from the summer storms we call monsoons. But these storms are highly localized—just a mile or two from a downpour it may remain completely dry. Also, the rains often fall fast and furious, resulting in runoff. Moisture fails to soak into the soil to benefit plant roots. Check soil moisture to be sure.
CARE
Mulch: to ease the pain Refresh the organic mulch you applied in May. (Winds and high temperatures can cause it to blow away and dissipate.) A layer up to 3" thick works well. Keep mulch away from the trunks of trees, especially citrus.
Pests, large and small: July is one of the most active times of the year for pests, and July is the most common month to see Tucson's infamous palo verde beetles. Destroy them if you can, before they can lay their eggs at the base of palo verdes and other desert trees. Inspect plants for more typical pests at least once a week (vegetables and fruits every few days) during the next few months. Grape-leaf skeletonizers attack grape leaves in waves throughout summer. Watch for slow-moving black moths as they fly around your vines. They want to lay their eggs on leaf undersides. Black-and-yellow caterpillars, with voracious appetites for grape leaves, follow. Clip and destroy infested leaves.
Check ties on vines: Long, hot summer days in combination with regular moisture can cause plants to grow rapidly. Loosen or remove plant ties on stakes of young trees and on vines to prevent serious damage.
Feed lawns and landscape plants: Regular summer waterings wash nutrients, especially nitrogen, out of plants' root zones, especially with lawns. Apply ammonium sulfate or similar high-nitrogen fertilizer.
AUGUST
From a gardener's viewpoint, August brings the summer heat, which tends to overstay its welcome. But relief lies just over the horizon, as temperatures cool from hot to warm by late September. Through this late-summer season, consistent, regular irrigation becomes job number one. This period marks the end of the long summer season and kicks off another—fall planting. During September and October, nurseries stock up on fresh plants, and botanical gardens host not-to-miss plant sales.
PLANTING
If possible, hold off on setting out landscape plants. Better gardening weather comes in about a month or so. Palms and hybrid-Bermuda-grass lawns prove exceptions—they establish better with warm soil and air temperatures. Consider preparing planting beds or dig holes for trees and shrubs that you'll plant in October. But try to hold off until one of those cool, overcast monsoon days when temperatures remain in the 80s or lower.
WATERING
Monsoon rains bring moisture and cooler temperatures this month, but storms remain highly localized. Sometimes we're lucky and sometimes we're not, depending on how the storm races across town on a particular afternoon. After a summer storm, see if the rainfall paid your plants any dividends—dig down into the soil around plants and check for moisture. Often, much less water reaches the plants' root zones than we imagine.
CARE
Lightly thin branches of young mesquites, acacias, and other canopy-forming trees so strong winds can blow through. Gusting winds during summer storms can catch in thick umbrella-shaped canopies, blowing trees over and destroying them. Watering deeply at the trees' drip line and beyond encourages a wide-spreading root system that will better stand up to strong winds. If trees have a drip system, move emitters outward each year as the tree grows and roots spread.
If your home experiences a power outage (somewhat common during summer storms), check irrigation-system timers to see if they were affected. Don't wait until the plants "tell" you with their lackluster appearance that they're not receiving enough water!
Feed citrus this month, as September and October may be too late to encourage new growth before the winter cold coming in November.
SEPTEMBER
Summer may linger, but cooler temperatures are on their way—we promise.
PLANTING
Some years September teases us with cooler temperatures, then comes back with a week or two of 100° weather. Watch and wait until you're sure the heat has passed before making your planting move. Once temperatures are steady in the low 90s to high 80s, you can begin planting landscape plants, including trees, shrubs, vines, ground covers, and ornamental grasses. Winter annuals such as petunias, violas, calendula, and sweet alyssum can also go in now through October, as can cool-season veggies and herbs. To prep annual, perennial, or vegetable beds, add 3"-4" of organic matter (ground bark, peat moss, forest mulch, or homemade compost) over the area. Add 1 pound of ammonium phosphate per 100 square feet. Mix thoroughly into the top 8"-10" of soil.
WATERING
September's warm, sometimes hot temperatures require diligence in watering, especially through mid-month. Check the soil for moisture and look plants over every few days for signs of moisture stress such as dull leaf color, drooping, or browning of leaf tips. Continue to mulch to reduce moisture loss via evaporation.
CARE
Fertilize landscape plants early this month. Feed roses and trim lightly; plants will respond with another show of blooms. Overseeding your Bermuda grass lawn? Don't fertilize. Allowing your Bermuda to remain as is and go dormant? Go ahead and fertilize. Water lawn, apply fertilizer evenly with a spreader or carefully by hand, then water again.
OCTOBER
Like the Baby Bear's porridge, October is not too hot or too cold—it's just right.
PLANTING
The summer heat eventually relents in October, making this the best month to plant in Tucson, as evidenced by plant sales at botanical gardens and well-stocked shelves at nurseries all over town. It's also time to sow most wildflower seed so you can be the envy of your neighbors come March and April. If you didn't plant cool-season vegetables and herbs in September, get them into the ground now.
WATERING
Continue regular irrigations this month, but begin to taper off in frequency, adding a little more time between waterings. You'll want to gradually harden plant tissues and slow new, tender growth that might be damaged by freezing temperatures coming in a month or so. Don't allow plants to suffer from lack of sufficient moisture, however. Routinely check them for signs of stress, as described under September watering.
CARE
When planting trees, don't remove lower branches along the trunks. These small branches help nourish the trunk, making it stronger. Prune them flush to the trunk after a few years' growth. Almost every urban landscape has Bermuda grass as an uninvited guest. If you have been unable to dig it out, consider using a glyphosate-based herbicide such as Roundup. Apply it only to actively growing plants. October brings the last opportunity for application before the Bermuda goes dormant. Apply carefully only to the Bermuda on a windless day, and follow all label directions. Repeat applications will probably be necessary for eradication.
NOVEMBER
Even though winter is just around the corner, the early November sun typically shines bright and warm on our shoulders as we work in our gardens. But soon—usually before the end of the month—cool, rainy weather begins the transition to winter. Take advantage of the mild temperatures these next few months if you’re planning major outdoor landscaping and planting projects. And, unless an early frost hits (the average first frost for Tucson comes in late November), there’s still time to extend the fall planting season—if you plant soon. Moderate air temperatures help soil retain summer warmth—creating a formula that allows plants to establish their root systems in ideal temperatures.
PLANTING
Early this month the soil remains warm and newly planted plants thrive. This honeymoon between plants and the weather cools as temperatures decrease. Plant just about anything: trees, shrubs, vines, ground covers, and perennials from containers. Sow wildflower seeds as well as coolseason herbs such as dill, cilantro, parsley, and sage. Set out cool-season annuals for color. Succession-plant cool-season vegetables to extend harvests. However, hold off on planting cold-tender plants (citrus, bougainvillea) until late spring.
WATERING
If the summer monsoon failed to materialize in your neighborhood, deep-soak established landscape plants. Even with monsoon rains, the drought of the past several years has taken a silent toll on many plants—even native species. Plants appreciate a good, long drink after the extended season of warm weather. Water newly planted wildflower seeds and plants a few times each week to help them become established. Taper off irrigation (this should have begun in October) to harden tissues of established frost-sensitive plants. November is also the time to adjust irrigation- system timers to deliver water less frequently.
CARE
Freezing temperatures can come without warning in November, so gather coverings (old sheets, blankets, shower curtains) before the cold weather begins. Your local television weather forecast often will advise when to cover cold-tender plants such as bougainvillea, citrus, and hibiscus.
DECEMBER
PLANTING
Cool weather puts an end to most landscape plantings. Succession-plant cool-season crops—radishes, lettuce, peas, carrots, and broccoli—to extend harvests.
WATERING
If it’s cool, reduce watering to once this month (water newly planted plants more frequently). If it feels like summer has come 6 months early, deep-water established plants a couple of times each month until spring.
CARE
A hard freeze can kill top growth of tender plants such as red bird of paradise and lantana. Not to worry though, as the roots are insulated by the soil, so the plant is alive despite its completely dead appearance. Wait to prune, however. Recycle fallen leaves and garden clippings into compost. It keeps them out of rapidly overflowing landfills and there’s no better mulch or soil amendment than compost. Provide winter vegetables with a dose of ammonium nitrate fertilizer from November through December. Below-freezing temperatures are possible all the way into April. Watch nightly weather reports for freeze warnings and have coverings on hand to protect coldtender plants.
JANUARY
PLANTING
A string of warm, sunny days this month can fool one into thinking that winter has passed - but that is seldom the case. Hardy landscape plants can now be planted from containers, but soil temperatures will be warmer by March. Bare-root roses and fruit trees may be planted early this month as well. Some Tucson gardeners set out tomato plants this month, beating the heat to achieve more productive yields. Shortseason varieties such as Early Girl do best. Sometimes the gambling gardener loses out to frost, but it's simple to replant.
WATERING
Rainfall and temperature help dictate watering frequency. With drought conditions in recent years, deep-soaking landscape plants regularly is advised. Dig down in tothe soil to check for moisture if you're not sure irrigation is needed. Make sure drip-irrigation timers are working and drip lines and emitters are operating properly. If you flood-irrigate with a hose, extend each watering basin so it circles the plant just beyond its drip line.
CARE
Prune: January and early February are some of the best times to prune many landscape plants. However, don't prune spring flowering shrubs and perennials now—wait until after flowering ceases.
Cold protection: Below-freezing temperatures can reach into April. Watch nightly weather reports and have old blankets, sheets, and tarps on hand to cover citrus, succulents, bougainvillea, and other cold-sensitive plants during the night.
Kill weeds: If we are blessed with February rains, they are usually gentle and soak into the soil. This kind of rain is ideal for our landscape plants but unforunately also for weed seeds. But the moist soil makes it easy to pull weeds out, roots and all. Do this before plants mature and set seeds.
Control pests: Inspect plants for thrips and aphids - they love to feed on tender new leaves and flower buds. Blast them off with a jet of water from the hose or spray with an insecticidal soap or homemade soap and water solution (1 teaspoon of dish soap in a gallon of water). Rinse off the soap-andwater solution with clear water after half an hour or so. Repeat as necessary.
Fertilize: Feed citrus with a citrus fertilizer if leaves are pale green and no sign of new growth appears. Rich, uniformly dark green leaves mean that the plant is doing fine. If so, wait until late spring to fertilize.
FEBRUARY
Nothing moves gardeners more than those first bright days of spring. It's difficult to resist the call of a clear early morning to get outdoors, dig in the dirt, and inhale the freshness and promise in the air. Spring truly is a time of renewal. Nurseries overflow with healthy plants looking for homes, so what are you waiting for? Give in to spring fever. Your yard will love you for it.
PLANTING
A string of warm, sunny days this month can fool one into thinking that winter has passed - but that is seldom the case. Hardy landscape plants can now be planted from containers, but soil temperatures will be warmer by March. Bare-root roses and fruit trees may be planted early this month as well. Some Tucson gardeners set out tomato plants this month, beating the heat to achieve more productive yields. Shortseason varieties such as Early Girl do best. Sometimes the gambling gardener loses out to frost, but it's simple to replant.
WATERING
Rainfall and temperature help dictate watering frequency. With drought conditions in recent years, deep-soaking landscape plants regularly is advised. Dig down in tothe soil to check for moisture if you're not sure irrigation is needed. Make sure drip-irrigation timers are working and drip lines and emitters are operating properly. If you flood-irrigate with a hose, extend each watering basin so it circles the plant just beyond its drip line.
CARE
Prune: January and early February are some of the best times to prune many landscape plants. However, don't prune spring flowering shrubs and perennials now—wait until after flowering ceases.
Cold protection: Below-freezing temperatures can reach into April. Watch nightly weather reports and have old blankets, sheets, and tarps on hand to cover citrus, succulents, bougainvillea, and other cold-sensitive plants during the night.
Kill weeds: If we are blessed with February rains, they are usually gentle and soak into the soil. This kind of rain is ideal for our landscape plants but unforunately also for weed seeds. But the moist soil makes it easy to pull weeds out, roots and all. Do this before plants mature and set seeds.
Control pests: Inspect plants for thrips and aphids - they love to feed on tender new leaves and flower buds. Blast them off with a jet of water from the hose or spray with an insecticidal soap or homemade soap and water solution (1 teaspoon of dish soap in a gallon of water). Rinse off the soap-andwater solution with clear water after half an hour or so. Repeat as necessary.
Fertilize: Feed citrus with a citrus fertilizer if leaves are pale green and no sign of new growth appears. Rich, uniformly dark green leaves mean that the plant is doing fine. If so, wait until late spring to fertilize.
MARCH
PLANTING
Landscape plants: If you missed getting landscape plants in the ground last October, March is the next-best planting month. It's too late to sow seeds for most annual wildflowers, so set out perennial wildflowers such as penstemon from containers. Wait to plant citrus and other cold-tender plants until late April.
WATERING
Plants going into the ground in March need water every few days, depending on temperature and winds. Observe plants closely and water before signs of stress by checking the soil for moisture. Add a few inches of mulch over the root area to help retain moisture.
CARE
If trees come from the nursery with the typical single stake tightly wrapped to the trunk, remove it. Replace with two or three stakes loosely tied about 6 inches from the trunk. Remove all stakes once a tree can stand alone - the sooner the better.
March is a good time to feed most plants with a fertilizer high in nitrogen, such as ammonium sulfate. Feed roses with a complete rose fertilizer. Don't fertilize fruit trees (including citrus) if they have flowers, are producing new leaves, or have small developing fruit - flowers or fruit may drop prematurely.
Scott Millard is the author and editor of more than 30 gardening books.