Depends on the type of hydrangea and where in zone 10B :-) In coastal SoCal, Hydrangea macrophylla are best grown in bright all day shade or filtered/dappled shade.

I let mine get morning summer sun until 11am; you can try the same or a few hour(s) less. If it gets too much sun in the summer, you may notice that the leaves in direct sun will turn all yellow, including the leaf veins, while the other leaves underneath remain dark green. If that happens then transplant it.

I would also recommend not placing them in windy locations (think Santa Ana winds if in Z10b). The big leaves of macs tend to loose moisture faster than the roots can absorb in Year 1 and maybe 2 and windy sites can make this moisture loss happen faster, making you water more often to compensate. A wind block might help when the S/A winds come in the fall. 75% shade cloth might also help with the sun.

If you see the leaves browning from the edges inwards, the leaves are loosing moisture too fast. About 2-4" of organic mulch up to the drip line might also help. Water the plants from the center "crown" outwards and water enough to get the soil moist deeply. I insert a finger into the soil to a depth of 4" and water if the soil feels dry or almost dry. A soil moisture meter might also help.

Kathy, are you in California too like wandac0917?

Yes, Ventura county sunset zone 20. Historical low 23*F, usual annual minimum about 30*F so I call it 10a but buy for 9 as I hate losing plants. Hot was 100*F last week and it's cooled to a nice 80*F during day and 65 at night for the next week.

Wow, pretty close to our weather. I have not been watching the weather news lately but whatever cooled us down from the 100s must have stoped by your doorstep too; we cooled from the 100s to 85 and a low around 75. Hooray for the rain!

I live in Miami . zone 10B. will Hydrangeas only grow farther north in 10A.... I miss the gorgeous huge flowers that everyone stops to admire. And my Mom had them so I would love to keep that memory going.

Well, they are able to grow bigleaf hydrangeas successfully in Puerto Rico, parts of Mexico and central America, the Azores and Canary Islands and in Hawaii. And all of those are zone 10 and above.

Hardness zones only refer to average minimum winter temperatures. They have NO basis or influence on how a plant might perform during the actual growing season. Other factors, which may be limiting, come into play there.

Thank you so much!!! Do I just look for “big leaf” hydrangeas at local Home Depot or nursery?

Hydrangea macrophylla cultivars ('macrophylla' means big leaf).