Beautiful hydrangeas are in bloom throughout the area landscape. White, pink, blue, purple and many mixed color combinations catch your attention wherever they grow. It is hard to imagine summer without hydrangeas blooming.
There are always a couple of questions folks want answered when talk turns to hydrangeas.
The top hydrangea question always asked is, how do I get my hydrangea to turn blue? It is the big leaf hydrangeas that will turn color. If your hydrangea is white, it will not turn any other color, regardless of what you do.
The bloom color is determined by the soil acidity. If blue or purple blooms are desired, apply sulfur or aluminum sulfate to the soil around the hydrangea and work it in. If a pink bloom is desired, apply lime several times during the warm season and work it into the soil around the hydrangea. For either blue, purple or pink blooms, it may take all season for the color to change, or even into the next year. It takes time for the roots to absorb the chemicals that change the bloom color. “Endless Summer,” is a big leaf, blue bloomed hydrangea that works well in this area. This hydrangea tolerates cold weather better than some of the other hydrangeas.
The next most popular question is, when do you prune the hydrangea? I only prune the dead out, when it is truly dead, in the winter when the shrub is hibernating. “Endless Summer,” blooms on old and new growth. If you have dead branches and remove them, you lose no blooms. If your hydrangea is growing too big for the area you selected for the shrub to grow in, it is not the hydrangea that needs pruning, but the hydrangea needs moving to an area where it can spread out and up. If you need a shrub to stay small and blend into a spot in a border somewhere, look at the varieties available for small spaces and select one from there to fill the spot. The hydrangea will grow as it is programmed by nature, you cannot change that. OK, you say, I will prune it and keep it small. Yes, you can, but you will sacrifice blooms, every year, as you will have to prune the shrub every year to keep the shape and height you need to fit into that particular area. It is best for you and the shrub, if you plant a hydrangea that will fit into small spaces, and not try and make the shrub fit in the small area by the machinations of yearly pruning. Both you and the shrub will be much happier.
Another frequent question is, how do I get rid of powdery mildew? There are many answers to this question. I will tell you what I do. First be sure you have powdery mildew. If there is any question, ask someone who can diagnose plant diseases, such as your local extension or experienced garden club member. If it is powdery mildew, I have tried several things. I don’t use any chemicals on my plants that will harm pollinators.
I have used powdered milk (reconstituted), placed the milk into a gallon garden sprayer and sprayed all the leaves and stems of the plant until they are dripping. I do this at the hottest time of the day, so the sun will burn off the mold with the milk. This does work. The leaves are very shiny afterwards and look healthy. The problem with this is, if you have an established mold problem, you will have to do this frequently all season and after it rains. It is best to start doing this as soon as you see any new shrub growth, very early spring.
There are other recipes for spray, such as one tablespoon of baking soda, one tablespoon of neem oil and one tablespoon of blue Dawn, all mixed together, into the gallon of water and applied on the leaves and stems. I am not sure it is the recipe that counts as much as the consistency in treating the mold.
No matter what you use, all infected foliage should be picked up and burned. Do not add this to any compost pile, as you will be spreading the mold. Give all your tools a Clorox dip and wipe them down and wash your gloves in hot water. Good hygiene will pay off, even when it looks like you are losing the battle. Hot summers, heavy moist air, restricted air flow around the plants can all help powdery mildew along. Do your best to keep up and see if you can keep “old moldy” under control. Your shrubs will love you for it.
Master gardener Fredi Stangland resides in Medina.