Using a bird feeder to attract squirrels may motivate them to set up shop in the garage or attic of your home. Even though close to the reliable food source, this setup can lead to structure damage. Planting a walnut tree (Juglans spp.) is a better option, because the tree offers both shelter and food to the squirrels. The deciduous tree also adds ornamental value to your property and many varieties are hardy to U.S. Department of Agriculture Plant Hardiness Zones 4 through 9.
Test the soil to determine its pH. Walnut trees thrive in a soil with a pH between 6.5 and 7.2. Amend the soil based on the test results; work lime into the top 7 inches of soil to raise the pH or add sulfur to lower it.
Select a planting location that has full sun, because walnut trees are not shade-tolerant. Look for good airflow and shelter from heavy winds. Find an area that allows you to easily see the tree and the squirrels from inside the house. Consider planting near an area with overhead power lines, because squirrels often use these to get around. Avoid areas where pets roam and don’t plant near walkways and car parks, because falling nuts can cause injuries and damage.
Cultivate the soil to a depth of 2 to 3 feet. Remove weeds in a 2-feet radius around the planting site, to avoid competition for nutrients. Incorporate a 2-inch layer of compost into the soil to promote soil moisture retention. Aim for a well-drained soil that retains moisture — flooding during the growing season can kill newly planted walnut trees.
Dig a hole that’s large enough to fit the root system of the walnut tree seedling. Place the tree in the hole and backfill it halfway. Tamp down the soil with your foot to firm it and eliminate air pockets. Continue backfilling the hole and once it’s level to the soil surface, tamp down the soil once more. Check that the tree is upright in the hole and add a 1-inch layer of soil on top of the backfill. Plant the tree at the same depth as it was in the nursery, after the last spring frost date.
Trickle water from a garden hose or watering can on the soil around the tree so the moisture is slowly absorbed. Water the tree deeply to reach its roots. Provide about 1/2 gallon of water once a week and increase it to 1 to 2 gallons during hot weather. Adjust the amount of water you provide after rainfall.
Spread a 3-inch layer of organic mulch, such as wood chips, on the soil around the walnut tree seedling to suppress weeds and promote soil moisture retention. Keep a 2-inch distance between the mulch and the tree at all times.
Fertilize the tree with an organic nitrogen fertilizer after three years, to make up for the nitrogen used during decomposition of the organic mulch. Feed the walnut tree each year hereafter, and after 10 years, feed the tree twice a year. Alternatively, perform another soil test for a clear indication of the soil pH and the needed amendments.
Once your tree has matured, attach one or more squirrel nest boxes to it, to provide housing for the squirrels.
To discourage squirrels from raiding and damaging bird feeders, use seed, such as safflower seed, that they dislike, or provide them with a squirrel feeder stocked with squirrel food.
When using weed killer to get rid of weeds, always use an all-natural, animal-safe product.
University of Florida IFAS Extension: Feeding Squirrels
Learn2Grow: Juglans Nigra
Purdue University Cooperative Extension Service: Black Walnut Plantation Management
University of Minnesota Extension: Growing Black Walnut