Viewing post #2230293 by dsisinni

luis_pr said:When this problem happens in the summer months, I would say that there is a soil moisture issue. But in your area, the highest temperature so far this year is 78F in April.

I would observe the brown leaf areas and try to determine if they are "growing" or not. If not, it is possible that they were caused by winter damage in the form of very, very cold temperatures or in the form of late frosts like you are about to have. If the brown areas are "growing", it could be caused by not enough water or by insect pests. If hydrangeas do not get enough water, they zap the flower buds and open blooms first, then the leaves begin to brown out from the edges inwards.

There are some insect pests that can be out there this time of the year. They cause the new foliage to be curled, etc. Others can nibble at the ends of the leaves. But again, it sounds like your temperatures are too cold still. Be prepared to protect the leaves and the invisible flower buds located at the ends of the stems. Those will produce early Spring blooms. The new growth that is coming from the crown/base, if it gets tall enough and old enough, will later on produce a second flush of blooms.

The affected areas are small. At this time, if it is not changing in size, I would not worry.

One suggestion... since you have a source of humidity and since humidity promotes powdery mildew and cercospora leaf spots in hydrangea mopheads, water the soil and never the leaves. If you use a sprinkler, make it water the hydrangeas around 6-8am so the sun will promptly evaporate any water drops in the leaves.

Another suggestion: start with 1 gallon of water per plant when you see leaf out in Spring. When temps are regularly above 85F most days then ratchet up the amount of water. Say to 1.5 gallons per plant. Should temps reach and stay above 95F, increase the amount of water to 2 gallons. When temps cool down in the Fall, reverse the process. Reduce the amt of water from 2 gallons to 1.5 gallons when temps are typically below 95F. Then reduce the amt of water to 1 gallon when temps are below 85F. Then reduce waterings to once a week or once every two weeks (depending on local rains) when the plants go dormant and all the leaves have browned out. Stop watering when the soil freezes. Resume Spring watering levels when you see leaf out. As the plants get larger, you will need to water more. The amount of water suggested (1 gallon in Spring) should get soil moist down to 8" but, if you insert a finger and it does not feel moist down to 8" of depth, use more than 1 gallon. To tell when to water: insert a finger into the soil to depth of 4" and only water when the soil feels dry or almost dry. Water the soil but never the leaves.

FYI: your average date of last frost is around the end of the first week or first two weeks in May so, this upcoming freezing temps may be the last one this year.

Thank you so much for all of this info - it is reassuring that, for now, it seems as though the plants may be okay and just need some extra care during the last cold spell of spring. I'm planning on covering the hydrangeas with plastic rubbermaid containers and further considering stuffing the inside of the containers with straw for extra warmth.

Thanks again for your quick response!