The former tenant in my apartment left her plants in the backyard, so in Spring I had pots full of sprouting plants but I had no idea what each plant was. I immediately recognized the 2 pots of hydrangeas that began sprouting pretty early in the spring, and one of the pots still contained dried hydrangea flowerheads from last year.
Hydrangeas are amazing: the flowers on the plant change color in reaction to their environment!
Soil that is heavy in aluminum will produce plants with blue flowers. Alkaline soil produces pink or purple flowers. A pH neutral soil will produce white flowers, which is the most common.
I've heard this story before: a person buys a blue hydrangea bush in bloom from a garden center and transplants it into her front yard. The next Spring, the flowers are suddenly blooming white! It's because the plant has moved to a new environment, and the flowers have adjusted themselves accordingly.
Normally, if you want to force blue hydrangeas in your front yard, it's pretty difficult to dig up and replace all the soil in your yard to produce this effect. But here in FarmTina land, where all of my plants are growing in containers, I can easily play around with altering the color of my flowers.
The one thing I can't adjust is the intensity of the color. This is mostly a reaction to the weather, mixed in with the genes of the plant. An alkaline soil can nudge the plant to produce pink flowers, but they may be anywhere from pale pastel pink to brilliant magenta.
<-- Here are my hydrangeas right now. They should begin blooming pretty soon!I've been wondering: Could I plant hydrangeas in soil beds along with my vegetables and use the hydrangea color as a soil pH indicator? I bought a fancy soil tester so I can test my soil and adjust the N P K and pH levels for maximum health and production. Maybe next year, I'll sell the fancy soil tester on eBay, plant hydrangeas in each vegetable bed and adjust the soil according to the color of the hydrangea flower!
Does that sound reliable?