The Randle Oak, a giant southern red oak, grows near the pond’s edge. The tree evokes memories of countless laughter-filled family picnics held beneath its leafy expanse. The massive low-hanging boughs now gently embrace my parent’s memorial, forming a natural canopy that shelters cheery flowers amid a rock garden.
Suspended from the oak, Ned and Ernie’s cedar swing rocks empty in the gentle breeze. Their ashes rest in cool shade near the tree’s century old trunk. Acorns from last year’s drop have sprouted in a nearby seedbed. The seedlings will be planted soon, each with the ability to conjure fond memories in the minds of this family.
Many people have emotional attachments to specific trees. Perhaps you have a special oak tree, too. Growing your own oaks is easy and a fun activity for the whole family. It provides children with a wonderful opportunity to learn about a tree’s life cycle, sustainable resources and how they can play a big part.
Growing oaks is an effective wildlife and habitat management tool whether it applies to your backyard or back 40. Oaks enhance wildlife viewing and hunting opportunities by attracting a variety of wildlife with food, cover and nesting habitat. Likewise, mature oak trees provide humans with food, lumber, fuel, watershed protection, shade and a lot of beauty.
Following are general guidelines and tips to help you grow oaks from acorns and start “putting down roots.”
IDENTIFY THE TREES
The mighty oak has long been prized for its longevity, strength and unparalleled wood properties. There are about 400 species of trees and shrubs in the northern hemisphere that have the term oak in their common name. They include deciduous and evergreen varieties that grow in a range of climates from cold to tropical.
Characteristic to oaks are spirally arranged leaves with lobed, serrated or smooth edges. In spring, flowers called catkins are produced. Oak fruits are nuts called acorns that contain one seed (rarely two or three), and take 6 to 18 months to mature depending on the species.
All oaks belong to the beech tree family and are divided into two categories: white oak and red oak. Leaves of trees in the white oak group have rounded lobes and no spines at the lobe tips. White, swamp, bur and chestnut oak are examples. Members of the red oak group including northern and southern red oaks, pin, Shumard, black and Nutall’s exhibit more angular lobes generally, and small points or spines at the tips.
Use a tree identification guide to identify individual species. Ask a local forester or county extension agent if you need planting guidelines and the acorn drop dates in your area.
Experts advise harvesting acorns in your local area for best results. Ripening dates can vary from year to year, state to state and species type by as much as a month but generally collection is done from August to December with prime time from late September through early November. What’s the best time in your area to start collecting? When they start falling!
Choose trees that are easily accessed and heavily loaded with acorns. Trees growing near churches, schools or parking lots are easier to identify and the acorns there are easier to collect. When the majority of acorns are falling, it is best to gather those that are dark, plump, free of holes and detach easily from the cup. Carefully place in containers labeled according to the tree type. Keep them in the shade as you collect them. Heat and drying will cause the acorns to lose their ability to germinate quickly.
PREP FOR PLANTING
Place the acorns in a bowl or bucket of water. Discard the floaters. Sort the “keepers” according to type.
Place the acorns in a refrigerator as soon as possible. Polyethylene plastic bags of 4 to 10 mil thickness are recommended for storing refrigerated acorns. They are permeable to oxygen and carbon dioxide but impermeable to moisture.
An alternative is Ziploc bags with pinholes punched for ventilation. Use dampened sawdust, peat mix or a paper towel in each bag. Label bags with the species name and parent tree location. Refrigerate the loosely closed bag(s) at 40 degrees F. and keep acorns barely damp throughout the winter.
PLANTING ACORNS: Red oak group acorns mature in two seasons and are planted the following spring. They require about 1,000 hours of cold or about 42 days. This process is called stratification or exposing seed to cold temperatures to prime it for sprouting. Red oak acorns can be planted anytime after stratification. White oak acorns mature in one season, the season they are collected. Plant anytime after collection or refrigerate for later planting using the same guidelines for red oaks. Note: white oak acorns can sprout at 36 to 39 degrees F.
PLANTING IN A SEEDBED: Select an outside seedbed that is well drained and receives full sun. When planting large numbers of acorns outside, seedbeds are easier to use because nature will provide the right conditions most of the time and watering will be necessary only during dry spells. Choose areas such as a flowerbed or vegetable garden that are not subject to animal browsing. Young seedlings are tasty and tempting to deer, rabbits, moles, voles and other mammals.
Prepare the seedbed by tilling and incorporating organic material if improved drainage is required. Plant the acorns 6 to 8 inches apart on their side about 1 inch deep, or deeper for especially large acorns. Water the area thoroughly after planting.
Seedlings will begin to emerge from the soil after several days or weeks. Remove inferior, smaller seedlings to encourage the development of the stronger ones. Ensure that seedlings have adequate space so that each leaf receives sunlight. When rainfall is inadequate, water weekly.
PLANTING IN A POT: Propagate seedlings in pots that have drainage holes and are a minimum of 1 foot deep to allow roots to develop. Fill with a mixture of potting soil and soil from your garden. Plant several acorns on their side in each pot at least twice the depth of the acorn. Keep the soil moist but don’t overwater or it will cause rot.
After seedlings emerge remove inferior seedlings, leaving the largest one in each pot. Add a slow-release fertilizer or organic fertilizer at half the rate every six weeks. Indoor pots may be placed outdoors in early spring. Do not allow the pots to freeze. Locate in a partially shaded location for a month or so to acclimate them to a sunny location for maximum growth. Monitor water requirements.
TRANSPLANT SEEDLINGS: Generally, transplant seedlings in pots anytime after the first leaves open and become firm and/or prior to extensive root development. Don’t allow an oak seedling’s taproot to grow out of the container bottom into the soil below or breakage will occur. Seedlings grown in seedbeds can be transplanted in late winter or early spring, depending on your location, weather and soil conditions.
Oaks adapt well in natural forest settings, inner city parks, and suburban yards. Select a sunny location with plenty of growing space since most oaks are large at maturity. Dig a hole twice as wide and deep as the pot or root ball. Add organic matter if needed.
PLANTING TECHNIQUE: Set the root ball gently in the hole with the root crown at the level of the soil surface. Fill the hole with soil, tamp firmly and soak with water. Consider planting two or three seedlings per location and later remove all but the most vigorous. Construct wire rings or install tree tubes to protect the seedlings from animal damage such as deer browsing. Attach a marker with tree type if desired. Seedling tubes or shelters are available from forestry and garden suppliers.
Collecting acorns and growing seedlings makes a fine school project. Neighborhood groups can grow seedlings to plant trees along streets and in common areas. Charities or special interest groups can grow and sell seedlings from a memorable tree as a fund-raising project. Your special oak can do good things for others, too.
For more information and assistance on growing oak trees from acorns in your area contact a local forester or county extension office.
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