Thank you for being one of our most loyal readers. Please consider supporting community journalism by subscribing.
Hydrangeas bloom depending on species from spring through summer. The Wilson Botanical Gardens has a great assortment of lace caps, mop heads and panicle hydrangeas.
The lace cap hydrangea is the flower that changes its color based on the soil pH. If your soil pH is 5.0 to 5.5 then you will have blue flowers. Likewise, if your soil pH is 6.0 to 6.5 you will have pink flowers. It does take a while to adjust your soil pH, so if you are not happy with your flower color, now is the time to soil test.
You can get soil kit boxes, free of charge and without personal contact, at the Wilson Ag Center Extension office, 1806 SW Goldsboro St. The soil kits are in the hallway, and you can return full kits to the same location. Once they arrive at the N.C. Department of Agriculture, the soil lab will work its magic and then provide you recommendations on the amount of lime and fertilizer you need to keep your hydrangeas healthy.
Thinking ahead to summer high temperatures, one plant that typically suffers includes our beloved hydrangeas.
Leaf spot is a common complaint. This leaf spot is called Cercospora, a fungus. It does affect all of the hydrangea species we grow here including smooth, panicle, oakleaf and big leaf types. I see it more commonly on smooth and big leaf types of hydrangeas.
The disease usually starts in July and lasts until October. But the good news is the disease is considered an aesthetic problem only. We do not recommend any fungicides to be sprayed. The best way to reduce the occurrence of this leaf spot is to plant hydrangeas in the correct location, which is shade or at least afternoon shade.
Reducing overhead watering is recommended. If you water your hydrangeas, try to limit the water to the base of the plant by using soaker or drip hoses. If you have overhead irrigation, try to water early in the morning so the foliage will dry quickly. Splashing water can also spread the disease. Humidity may also play a role in keeping leaves wet. This leaf spot disease tends to start on older foliage first and then spread up the plant. Removal of the older leaves can also help reduce the spread. Initial spots are purplish in color, and as the circular spots enlarge they can turn tan or gray in the center.
If you are in the market for a new hydrangea, select a cultivar that is less susceptible to this disease. A few of these include “Blue Bird” and “Forever Pink.”
This fall it is very important to rake up and remove all fallen leaves since the fungus can overwinter in our climate.
For more information join us for our Virtual Garden Talks: Hidden Habits of Hydrangeas by registering at tinyurl.com/yao78cr8 or contact the Wilson Extension Master Gardener Volunteers at 252-237-0113 or email anytime at email@example.com.
Cyndi Lauderdale is horticulture extension agent with N.C. Cooperative Extension.