Proper timing promotes better blooms and increased plant vigor.
Getty Images
Hydrangeas remain a fan-favorite among gardeners for one simple reason: gorgeous, long-lasting blooms.
Unlock the secret to lushhydrangeasthrough proper fertilizer selection and timing.
Credit:Getty Images
However, fertilizer pop in and timing of applications are critical to producing the desired response.
Fertilizing too much or at the wrong time can encourage leaf production over blooms.
And the flower color of some hydrangea species is sensitive to soil pH and available nutrients.
As a general rule, hydrangeas respond well to slow-release, granular fertilizers formulated for woody plants.
Slow-release fertilizers can be organic or inorganic.
These naturally release nutrients slowly as the organic matter breaks down in the soil.
Rose-tone is an organic fertilizer that works well on mosthydrangeas.
Slow-release fertilizers for woody plants typically have an NPK ratio of 3-1-2 or 3-1-1 (e.g.
24-8-16 or 15-5-5).
Hydrangeas utilize aluminum available in the soil to produce blue and purple tones.
The more aluminum these plants can take up from the soil, the more intense their flower color.
In the absence of aluminum, flower color becomes pink.
When phosphorous levels in the soil are too high, the plant cannot absorb the necessary aluminum.
Soil pH also plays a part.
However, varieties with blue and purple blooms sometimes require additional soil amendments to adjust soil pH.
Conduct a soil test to identify the existing conditions.
Test results will indicate how much powdered or pelletized sulfur is required to reach the desired pH.
Soil tests will also determine if sufficient aluminum is available in the soil.
Begin fertilizing newly installed plants the following spring.
This treatment is helpful if soil tests indicate insufficient amounts of aluminum in the soil.
It provides a quick fix through the utility of a fast-acting liquid soil drench around the plant.
Applications of aluminum sulfate should not replace efforts to amend soil pH, which produces long lasting results.
With regular spring fertilization, this tool should become unnecessary over time.
These varieties produce flower buds during the summer that will open next season .
A mid-summer fertilizer app helps support flower bud development.
Be sure to stop fertilizing hydrangeas by late July.
New plants typically have plenty of slow-release fertilizer incorporated into their potting medium to last through the growing season.
How To Fertilize Hydrangeas
Fertilizing hydrangeas couldnt be easier.
This is called the drip line.
Extend applications three to four inches beyond the drip line for every foot of plant height.
For example, fertilize a three-foot hydrangea 9 to 12 inches beyond the drip line.
Keep the fertilizer off foliage and branches to avoid burning plant tissues.
Soil moisture hastens the movement of nutrients through the soil and keeps materials in place.
see to it the soil is slightly moist before applying fertilizer.
Avoid applying fertilizer to dry soils as the nutrients can burn roots.
A good practice is to water the planting area the day before you intend to fertilize.
Water lightly again after system.
Adequate soil moisture is necessary to dissolve the nutrients and carry them to plant roots.
This improves the soils capacity to hold water and nutrients and is a great way to build healthy soil.
Compost provides the primary nutrients plants neednitrogen, phosphorous, and potassiumas well as important micronutrients.
In fact, too much of certain nutrients can lead to poor flowering.
Excess nitrogen encourages lush foliage growth and stem development at the expense of flowers.
And weve already discussed how too much phosphorous can impact flower color.
Of course, soil can also be deficient in important nutrients.
Yellowing foliage in the center of the plant during flowering may indicate nitrogen deficiency.
Applying a fast-acting liquid fertilizer can remedy the situation.
Iron deficiency can also be a problem for hydrangeas and triggers when the soil pH is too high.
Iron deficiency causes young leaves to turn yellow between the veins, which remain bright green.
