Some gardeners report success in turning their hydrangeas blue by applying coffee grounds to the soil. The coffee grounds make the soil more acidic, allowing the hydrangea to more easily absorb aluminum. In addition, fruit peels, lawn clippings, peat moss and pine needles, are thought to have a similar effect.
Start adding coffee grounds to the soil surrounding your hydrangeas in late fall. Sprinkle them around your hydrangeas, but be sure to work them into the soil to help eliminate any off-putting smell. You do not need to do this process often–just two to three times per year should be sufficient.
Excessive acidic soil can kill or hamper the growth of plants like asparagus fern, Chinese mustard, Italian ryegrass, lavender, orchids, rosemary, tomatoes, and geranium. The roots of these plants are also not potent to absorb the nutrients added by the coffee grounds in the soil.
If your soil is more alkaline, your hydrangeas will be pink or even purple. According to Garden Design, adding lime or eggshells to the soil will ensure a pinker color, while adding aluminum sulfate, pine needles, or coffee grounds can give your hydrangeas the blues.
Balanced granular fertilizers such as Espoma Rose Tone and Holly Tone are good choices. Jobes Fertilizer Spikes are another good option. Avoid using fast-release fertilizers in liquid form on hydrangeas. These products can stimulate growth in the short term but may not sustain the plant for the long haul.
Miracle-Gro Performance Organics Blooms Nutrition
This is an all-purpose blossom booster that's suitable for use on a wide variety of perennial and annual blooming plants, including hydrangeas. It provides various minerals, including copper, calcium, and iron, to supplement common nutrient deficiencies.
Some gardeners report success in turning their hydrangeas blue by applying coffee grounds to the soil. The coffee grounds make the soil more acidic, allowing the hydrangea to more easily absorb aluminum. In addition, fruit peels, lawn clippings, peat moss and pine needles, are thought to have a similar effect.
There is one more trick up the apple cider vinegar sleeve: You can actually change the color of hydrangea flowers from pink to blue. Hydrangea flowers will be pink in alkaline soil, but change to blue in acidic soil. So, mix up some apple cider vinegar and water, and give all the acid-loving plants a treat.
Hydrangea Care Tips
Water at a rate of 1 inch per week throughout the growing season. Deeply water 3 times a week to encourage root growth. Bigleaf and smooth hydrangeas require more water, but all varieties benefit from consistent moisture.
Don't just pour it down the drain — you can use it to fertilize your plants, both indoor and outdoor. Coffee grounds (and brewed coffee) are a source of nitrogen for plants, producing healthy green growth and strong stems. Coffee also contains calcium and magnesium — both of which are beneficial to plant health.
Coffee Grounds to Deter Pests
Coffee grounds are commonly used to keep animals including slugs, snails, rabbits and fire ants from eating plants in the garden, and to keep cats from treating garden beds like litter boxes.
Compost coffee grounds for a vegetable garden instead of using them directly. Remember, coffee grounds are not good for tomatoes or seedlings. Get a soil test, especially if your plants are not thriving or you want to change the acidity of the soil.
Yes, it's possible, but it should not be more than a thin sprinkling. If you add too much, the coffee grounds will form a dense layer on the surface of the potting soil that is impenetrable to water. On a regular basis, using leftover coffee to water your potted plants is a much better idea.
Cover the soil around the plant's trunk with well-dried coffee grounds and water abundantly. Each watering will release nitrogen from the coffee grits and penetrate into the soil with water, soaking the plant's root system, thereby strengthening it and protecting it from pests.
However, many times it's easy to turn those pink imposters back to blue, should one so desire. Simply squeezing a few lemons or limes over the plant somewhat raises the acidity level of the soil, consequently turning the blooms from pink to blue.
A Little Goes a Long Way. Baking soda is the secret, but keep in mind that a little bit does go a long way. To apply it to your wilted hydrangeas, mix 1 tablespoon of baking soda into 2 quarts of water. Stir to be sure the baking soda thoroughly dissolves.
Hydrangeas produce a “sap” that clogs their stems and blocks water from traveling up it to those gorgeous blooms. The boiling water helps to do away with the sap.
Make a vertical slit in the incision and hold the stem upright in the boiling water for about 60 seconds. Place the hydrangeas back in your floral arrangement and they should revive themselves in an hour or so.
Hydrangeas that bloom on new wood can be safely pruned in late fall once the plants have gone dormant or in early spring. Next year's flower buds won't be formed until late spring the same year they bloom, so there is no risk of removing the buds if you prune in fall or spring.