If you want a beautiful plant and a full harvest of tart and tangy elderberries, adding fertilizer is task you can’t put off if you want to fully enjoy the fruits of your labor.
Test Your Soil
Ideally, you would conduct a soil test before planting your elderberry shrub to determine the pH level of the soil, and any nutrient deficiencies.
After you have amended your soil with compost and planted your shrub, it’s not recommended to apply any additional fertilizer it in the first year of growth.
testing garden soil here.
Choose Your Fertilizer
You have lots of options when it comes to choosing a plant food for your elderberry shrubs.
10-10-10 (NPK) is a good option for most elderberry plants. The 10-10-10 refers to the amount of nitrogen (N), phosphorus (P), and potassium (K) in the mix.
In this case, the product contains 10 percent of each component.
You can find 10-10-10 fertilizers formulated specifically for berry plants. These typically include extras like sulfur. Sulfur can help lower the pH and increase the acidity of soil.
Elderberries prefer a slightly acidic soil pH between 5.5 and 6.5. You can also use lime to increase the pH if necessary.
Elderberry shrubs thrive in organically rich, moist, well-draining soil. At planting time, it helps to work plenty of compost or well-rotted manure into the soil, to ensure your young plant thrives.
But after the plant gets its beginning boost in the first year, you’ll need to apply some fertilizer to keep it thriving.
A general purpose granular garden food, such as this granular 10-10-10 Garden Food from Espoma, available at Nature Hills Nursery, can be applied, using 1/8 cup per plant.
Work carefully into the soil and water in well. If you have multiple plants, you can use 1 1/2 pounds of fertilizer per 100 square feet.
Elderberries have shallow roots, so use caution when working the product into the soil. Don’t dig deeper than three inches down.
growing your elderberry in a container.
If you’re using manure, make sure it’s well-rotted and composted to avoid burning the shallow roots. Gently work in two inches of the material all around the plant, keeping it away from the trunk.
I like to apply a spray of fish emulsion once a year when the fruit is beginning to set, to encourage a robust harvest. If you use fish emulsion, mix in a ratio of three tablespoons emulsion per gallon of water.
When to Fertilize
When you’ve decided which fertilizer you are going to use, you’ll need to know when to apply it.
Don’t fertilize your plants in the first year beyond that initial amendment with compost or manure that you may have worked into the soil.
Elderberries can sometimes use a little adjustment when it comes to the nitrogen in the soil.
Older plants may need a high nitrogen fertilizer like ammonium nitrate, ammonium sulfate, or urea, rather than a balanced 10-10-10 product.
Espoma Urea Plant Food is a high-nitrogen granular fertilizer and is available from Nature Hills Nursery.
You can apply at a rate of 1-2 pounds per 100 square feet, or 1 teaspoon around the drip line of your plant. Use once a year in springtime to promote vigorous leafy growth.
That’s because nitrogen is depleted over the growing season, while potassium and phosphorus might not be depleted as rapidly, so you might not need to add them at all.
You’ll know if this is the case if your plants seem to be producing few new canes, and the canes that are produced don’t grow as quickly or as large as they used to.
In that case, add high nitrogen fertilizer once a year in the spring, according to package instructions.
too much nitrogen may produce new foliar growth at the expense of fruit.
To recap: to add more nitrogen, select a high nitrogen fertilizer or work well-composted manure into the soil. To reduce nitrogen, select a low nitrogen fertilizer or a product with half the amount you normally use.
Watch Your Elderberries Grow
Fertilizer is just one component in creating a healthy, happy elderberry garden, but it’s an important one. Doing the job right will ensure you have a healthy vigorous plant, and an abundant harvest.
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Kristine Lofgren is a writer, photographer, reader, and gardening lover from outside Portland, Oregon. She was raised in the Utah desert, and made her way to the rainforests of the Pacific Northwest with her husband and two dogs in 2018. Her passion is focused these days on growing ornamental edibles, and foraging for food in the urban and suburban landscape.