GROWING ALMOND TREES
An almond is the edible pit of the fruit produced by the almond tree (Prunus dulcis syn. prunus amygdalus). Almonds are native to Iran and surrounding areas, but have been cultivated worldwide. The sweet almond can be enjoyed raw, while the bitter almond requires cooking to destroy it’s toxic compound to eat out of hand, or is used for almond flavoring extract. There are several different varieties of almond so it is important to choose one that is right for your area and how you want to use it.
Choosing a Variety
Almond trees grafted on Lovell peach rootstock can be maintained at 15-20‘ tall and wide. Almond trees grafted on Marianna 2624 plum rootstock can be maintained at 12-15‘ tall and wide.
Some almonds are self-fertile, others are not and require a different variety as a pollinizer (another almond or sometimes peach) to produce fruit.
The pollinizers should be planted no further than pollen carrying bees will fly, with no line of sight obstruction, to ensure proper cross-pollination. That distance varies with different bees, 100’ should be a good average distance.
Nuts ripen October in the Pacific Northwest.
USDA Hardiness Zone
Almond tree hardiness varies by variety, ranging from USDA zones 5-7 to 9. See individual descriptions for the specifics. This rating tells you the minimum winter temperature the plants typically survive when properly hardened off. On our web site you will find a USDA Hardiness Maps which provides information on the average minimum winter temperature in your location, by zip code.
Many plants native to locations that have cold winters have a Chill Hour requirement to ensure uniform waking up of flower and leaf buds in the spring. The chill hour requirement of plants varies by species, by cultivar, and sometimes by the level of dormancy achieved. If you live in a location in which winter temperatures seldom go below 40°F, and/or winters are short, you may need to select “low chill” cultivars of plants not considered tropical or sub-tropical. Ask at your local co-operative extension service to determine your usual accumulated Chill Hours. View our Chill Hours Chart for more explanation, a chart of typical winter chill hours, and a list of fruits and their typical chill requirements. Almonds require 500-600 chill hours.
Where to Plant Your Tree
Almonds need to be planted where they receive at least 8 hours of direct sunlight measured in early summer (late June to early August). Sufficient sun exposure triggers the initiation of new flower buds for the next growing season, without which there will be no fruit. Fruit ripening and flavor development are also benefited by the carbohydrate production stimulated by the sun, as well as it’s heat.
Almonds tolerate a wide variety of soils so long as they are well drained and moderately rich with a pH around 6.3-6.8 if on a plum rootstock, or pH 6.8-7.2 if on a peach rootstock . Improve your soil where you intend to plant by mixing an inch or two of plant based organic matter (manures are best for vegetable gardens), peat, or coconut coir into an area 1 1/2 to 2 times the diameter of the needed planting hole and up to a foot deep. A 2-4” deep layer of mulch (straw, leaves, or wood chips) applied after planting will continue to improve the soil.
Allow sufficient space for both the top of the tree and it’s roots when selecting the planting location. Refer to size descriptions for each variety, keeping in mind these are generally managed or pruned sizes, not maximum potential sizes. If you are planting an orchard be sure to include enough space between rows for transporting supplies in and fruit out.
Growing in Containers
Almonds generally grow too big to grow in a container for more than a couple years.
Do not use soil from your garden in the pot, instead use a potting soil mix with some added compost. For larger pots use a potting mix that has larger particles in addition to the smaller.
Care and Maintenance
Watering Your Tree
This is the most important and often the most difficult part of successfully growing plants. There are many factors, including the humidity, temperature, soil type, wind, and amount of direct sun that affect how much and how often water should be applied.
A general rule of thumb for plants in the ground is to ensure they receive an inch of water per week over the root zone. An inch of water is equivalent to about ¾ to one gallon per square foot of soil surface area. The typical three foot diameter planting hole would need 7 ½ to 10 gallons of water per week provided by rainfall or by the gardener.
Apply this water once a week, two times per week if soil is fast draining. This will of course depend on your own conditions and the plants you are growing! DO NOT water lightly each day because this results in a wet surface and dry root zone area. The soil should be moist but not soggy to a depth of about a foot for most growing plants. The top inch or two can feel dry, and the plant still be well watered. The trick is to have the water available where the roots are. In hotter and sunnier areas, a mulch of straw, bark, etc. can greatly ease the burden of summer watering. For plants in containers, water until the soil is saturated and water comes out of the drainage holes. Let the container dry until the soil is dry to the touch 1-2 inches down (more deep with deeper pots) and the container is lighter in weight. A plant that has wilted can be receiving either too much or too little water.
In rainy areas like the Pacific Northwest most of the plants that we offer will need relatively little supplemental irrigation ONCE THEY ARE WELL ESTABLISHED in the ground and have had a chance to develop a good root system. However even here it is important to make sure plants have regular, deep watering during the first couple of growing seasons, and the first summer is especially critical. In drier areas, or where soils do not retain water well, permanent irrigation is essential. Remember that you don’t want your trees to just survive, but rather to thrive. Make sure they get the water where they need it, starting at the drip line and extending away from the tree up to several feet ( for older trees) where the feeder roots will be. Drip irrigation and soaker hoses can be an efficient way to deliver the water.
For good steady growth and high productivity, your trees need to have adequate amounts of various mineral nutrients. Some people are fortunate and have naturally rich fertile soil. Many soils, however, are deficient in some nutrient or another and use of fertilizers, organic or chemical, can be highly beneficial if you want your trees to grow well. If you have a large gardener orchardist can be well worth it to have your soil analyzed by a qualified laboratory so you know for sure just what your soil needs. Typically this might cost $30-$60, depending on how detailed an analysis you want. Unless you know what is available in your soil, you will not be able to supplement it properly.
Use an all-purpose or balanced fertilizer like the organic fruit tree and shrub fertilizer. A couple of inches of well-rotted compost on the root zone can also be an effective fertilizer. A generous leaf or straw mulch around your trees will not only conserve moisture and help in weed control, but also keeps your soil healthy by building up humus, attracting earthworms, and supporting beneficial fungal organisms. This encourages young trees to be strong, healthy and productive. Use of concentrated products like chemical fertilizers or strong organics (for instance blood meal) is usually done from late winter through early summer. Applying fertilizer after early summer can encourage lots of soft new growth that is much more likely to be damaged by winter cold. Excessive use of fertilizer can in-crease disease problems on your plants and can even kill them. Use of too much fertilizer, whether chemical or organic, can contribute to stream and groundwater pollution, so please try not to use more than your trees really need. As a general guide, if your tree is producing about one foot of new growth or more a year and has healthy looking foliage, it may not need much or any fertilizer.
Pests and Diseases
Find out what insects and diseases are typical in your area. Ask your local co-operative extension professional what the typical insect and disease issues are in your area. Then you can make selections based on resistance or tolerance information available in our catalog, or, make a plan for controlling problems you can expect with the susceptible varieties you prefer to grow. If you see resistance information about a particular disease for one variety but not another of the same kind of fruit, then that variety may be susceptible or might not have been tested so is unknown. The following are some of the more common issues.
Sunken blackish cankers on stems or trunk, wilting and death of branches, gummy ooze from cankers, dead dormant buds.
Copper fungicide in early fall and again in January. Cauterize cankers with a torch in early summer. Apply foliar micronutrients to aid tree immune system.
This disease is most severe when spring frosts damage bark or when pruning is done in winter or early spring before bud break. Newly planted trees are especially susceptible.
Wilting and death of twigs and blossoms. Fruits turn rotten, gray-brown in color, often hanging from the tree as “mummies”.
Promptly remove any infected twigs or mummified fruits. Apply copper, sulfur, or lime-sulfur fungicide at petal fall, midsummer, and again in fall.
Blossom brown rot can be a difficult problem in very wet spring seasons. Spray promptly as soon as dry weather permits.
Peach Leaf Curl
New leaves blister, deform, turn reddish, and eventually die.
Plant resistant varieties. Lime and sulfur applied starting in mid-December. Spray are 3-4 week intervals.
Prevent infection by covering the trees from December to February to keep stems dry. Control times vary with climate. For low-chill varieties, apply spray 3-4 weeks earlier.
Dark olive green slug like larvae skeletonize leaves, especially common in summer
Insecticidal soap spinosad, pyrethrin, rotenone dust, or bioneem. Pick off and destroy by hand.
Trees can tolerate up to 25% defoliation with little harm. Not actually a slug; just resembles a slug. Also affects pear, plum, hawthorn, and mountain ash.
Shot Hole Disease/Corynium Blight
Small reddish-purple spots on leaves, which fall out leaving holes. Fruits may also be spot ted. On peaches, twigs may also be spotted and develop cankers.
Bordeaux mix or copper fungicides in early fall, winter, and spring.
Spores are spread primarily by splashing water, keep sprinkler water off foliage and fruit.
Small barnacle-like bumps on branches and leaves.
Dormant oil spray in early spring.
Insecticidal soap or soap/oil spray during juvenile phase.
Browsed shortened branches. Leaves are obviously munched on or plants are pulled up.
Fences or cages at least 8’ tall. Plastic mesh, electric, or woven wire fences.
At Raintree, an 8’ woven wire deer fence has worked best. Repellents don’t work consistently. and only trained large dogs patrolling the perimeter are effective. Some have had success with the product “Deerchaser.”
Fruits disappear or have gaping holes in them. Strawberries, blueberries, cherries and filberts are most susceptible but most fruits suffer occasionally.
Reflective Bird Scare Tape can work well. Bird netting. Cages.
Blue Jays start harvesting filberts when ready to pick, and so should you. Nuts dropped by jays are usually empty.
Bark eaten in a band from soil level up to 8” and roots eaten too, usually in snowy areas with lots of mulch or tall grass at base of trees.
Keep mulch 4”-6” away from trunk. Keep grass short and 1’-2’ from trunk. Use vinyl tree guard wrapped around trunk until tree well-established.
Voles and mice will chew a couple inches above ground and also into the root system. Rabbits will chew up to 8” high, particularly apple trees.
1/32 to 1/8” long pear shaped insects that multiply rapidly, espe- cially on the underside of leaves and on stems. Can be pink, green, black or white. Leaves show red blisters or are curled-down and stems turn black with sooty mold.
Natural predators like lady bugs and parasitic wasps often provide control. Knock aphids off with water spray. Spray with Pyrethrin, Rotenone, Insecticidal Soap, or delayed dormant oil. Control ants if they are also present.
Trees can tolerate some infestation. Monitor in late spring and summer. Control is more important on new trees. Grow plants that attract predators, i.e. dill or yarrow.
Numerous ants scurrying up and down the tree trunk; aphids, scale or mealybug present in large numbers, lots of sticky honeydew, perhaps sooty mold.
Find hill and apply pesticide. Apply Tangle Trap over 2-3” wide band of paper wrapped around trunk. Eliminate other pathways into tree.
Ants nurture and protect these insects in exchange for their sugary secretions. Insects may be difficult to control until the ants are controlled.
Brown Marmorated Stink Bug
Poking-type feeding damage followed by decay on fruits, nuts, berries and leaves. Deformity in the healthy tissue surrounding the dead tissue. Brown spots can show up in stored fruit.
Monitor with traps, some broad spectrum pesticides may work. Researchers are working on finding effective controls, but no info has been released yet.
BMSB over winters in groups in dry protected areas, such as houses. If you find them on or in your home use the vacuum, squishing releases their defensive stink. See stopbmsb.org for more info. Feeding begins in spring when the weather warms up and continues until new adults go dormant for winter.
Lesions on the upper surface of the leaf, or on the fruit or stems, followed by orangish structures on the bottom side of the leaf, or on the fruit or stems, which produce spores.
Copper fungicide after harvest before fall rains and again in early spring for prevention of some rusts. Remove and destroy infected parts of the plant. If possible select resistant varieties. Many varieties have not been studied.
Rust diseases require an alternate host, removing the host (within 900’ radius), applying fungicides, or removing infected parts may help. Check with your extension office to see what rust diseases in fruiting plants may be common in your area, and their alternate host.
Vertical splits in bark appear spring or early summer, usually on the south or east side of the tree. Disease or insect infestations may then occur.
Whitewash trunk and lower limbs with interior latex paint cut 50/50 with water each fall until bark has thickened. Avoid planting in frost pockets or where water collects in winter.
Injury occurs during pattern of warm days followed by freezing nights. Sap gets stuck in trunk, freezes, then rapidly thaws in the warm sun the next day, rupturing cells.