Caring for hydrangeas will produce showy, happy flowers that have the power to change color depending on the type of soil they are grown in.
Hydrangeas are probably the plants that you remember in your grandmother’s yard or garden. Because they steal attention, they are often planted at the corners of homes or at the focal points in gardens. It’s easy to landscape around them with other perennials and annuals. Besides being showy, what captivates folks is that they can change color, with the most notable ones being pink and blue.
I never gave these much thought until we were driving some backroads last year and I noticed a large, vibrant plant with cone-shaped blooms that started out cream-colored and slowly transitioned to pink. When we stopped to inquire, we were introduced to the Vanilla Strawberry Hydrangea. I was hooked and had to have one.
Since then, I have become hooked on all hydrangeas. At first, it was their large, vibrant blooms that caught my eye, but, since then, the fact that they are hardy plants that bloom year after year and add so much color and charm to gardens has moved them up among my favorite garden plants.
Get to Know Hydrangea
Also known as hortensias, hydrangeas are most commonly grown as shrubs but can also be trees or climbing vines. Some are so small that they can be planted in perennial borders, and some vines grow as high as 100 feet.
Besides their big, showy flowers, people are falling in love with them all over again because of their variety of shapes, sizes, and colors. Most species bloom from early spring to frost and come in shades of pink, blue, white, purple and green.
The word “hydrangea” comes from the Greek word hyder, meaning “water,” and angos, meaning “vessel.” Roughly translated, this means “water barrel,” which is aptly named for the up-shaped flowers that require lots of water. Here in the United States, hydrangeas are given for fourth anniversaries to symbolize appreciation and heartfelt emotion.
Selecting Hydrangeas
These showy flowers love sun to part sun. Since they get so thirsty, the best time to plant is in the spring or fall. The hot, dry summers are stressful for them to get started, since they require lots of water. Northern climates require a little more diligence to bed them down for the winter so they don’t winter kill.
Some folks have tried to make them houseplants, usually unsuccessfully, for many reasons. First and foremost, each variety needs its own amount of sunlight. Moisture and humidity are big failure factors. Indoor air tends to dry out faster, and hydrangeas like enough humidity without getting their feet wet. Even if you get these factors right, some varieties require cold periods of two to three months to hibernate.
Sadly, many “gift” hydrangeas from the stores are not bred to last more than one season. Their big, attractive flowers are the draw, but even though they are classified as perennials, they are more like annuals.
How to Change Hydrangea Colors
Of course, the big thing about hydrangeas is their ability to change color, depending on the nutrients, or lack of, that they receive. Primarily, their colors are either blue or pink. Unlike other plants, their colors can change dramatically, all by adjusting the pH of the soil. Some change color on their own when planted or transplanted, simply adjusting to their new environment. For this reason, during the first year, a plant can actually have more than one color of bloom at the same time.
This color change is due to the amount of aluminum in the soil. Either adding or subtracting this from the soil determines whether the blooms will be pink or blue. For this reason, it’s much easier to alter the pH of the soil if the hydrangeas are planted in pots.
Forcing pink blooms can be accomplished in different ways. Dolomitic lime can be added to the soil several times a year to raise the pH level. Aim for a pH of 6.0 to 6.2; if it rises above 6.2, you risk iron deficiency. They take up aluminum best at lower pH levels; raising the pH will help to keep the blue color.
On the other hand, if you want to change the color from pink to blue, add aluminum sulfate during the growing season to plants that are two to three years old, at a ratio of 1 tablespoon per 1 gallon of water. Water well in advance, as adding too much can burn the roots. Another method is to add organic matter, such as coffee grounds, fruit and vegetable peels, or grass clippings. For the aluminum to be available to the plants, the pH should be low, ideally around 5.2 to 5.5.
Caring for Hydrangeas
Be sure to fertilize with high levels of phosphorus, because the element helps protect from the aluminum creeping in. Use a ratio of 25/10/10 (phosphorus is the middle number). If aluminum occurs naturally in the soil, your best option is to grow hydrangeas in pots using a soilless mixture that likely doesn’t contain aluminum.
When fertilizing, choose a low-phosphorus, high-potassium mix; a 25/5/30 (potassium is the last number) mixture is good. If you have naturally high-alkaline soil, again, it is best to grow them in pots. Another thing to watch for is testing your water to make sure it is not contaminating your soil with unwanted minerals. Also, avoid planting by sidewalks or concrete as lime can leach out.
Color Galore
Although hydrangeas are primarily found in colors of pink and blue, you can find other colors. White hydrangeas are white; they cannot be altered. There is no such thing as true red, though hot climates can produce some almost-reds. Purple hydrangeas are among the most eye-catching and hard to come by. The soil conditions must be exactly right, the pH is directly centered, so purple is right between pink and blue. Heredity and plant health, as well as weather conditions, all affect the intensity of colors.
Now, what piqued my interest in hydrangeas in the first place was the ‘Vanilla Strawberry’ variety. Even the name itself is enough to draw you to it. It was developed in France by Jean Renault and is one variety of Panicle hydrangeas. Others in the group are ‘Strawberry Sundae’ and ‘Fire Light.’ ‘Vanilla Strawberry’ was voted top plant of the year by the American Nursery and Landscape Association in 2010. It is characterized by emerging creamy white cone-shaped blooms in mid-summer that slowly transition to pink and then strawberry pink in the fall. It is hardy, low-maintenance and sun-loving. As a bush, it grows nearly seven feet high and five feet wide. What’s not to love?
Besides their showy blooms, hydrangeas’ leaves produce large shady areas beneath them. These are perfect spots to plant shade-loving plants like hostas. Their colorful leaves add interest and more color to the area. You can also fill in with annuals to round out a planting area.
It boggles my mind that I have never discovered hydrangeas before. I love the idea of a plant that offers lots of color with low maintenance. No wonder I think of them as happy hydrangeas!
