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Ask The Expert: This is the first time I’ve tried to grow hydrangeas in pots; they are actually doing very well. My first plant was purple that I bought in April, the color now is a greenish color, (very beautiful color). I also have a light pink (called white spirit) and burgundy color. How do I keep the color purple, pink or even blue? What plant food is best, and anything else that keeps my hydrangeas beautiful in pots. Thank You for your help in this matter. -Juanita
Flower Shop Network Plant Expert Reply: Juanita,
Eventually you will need to re-plant the hydrangeas in the ground. I am assuming that you have Mophead hydrangeas (Hydrangea macrophylla). These types of hydrangea bloom-colors are controlled by soil conditions, specifically the pH of the soil.
- To keep a hydrangea pink you would amend the soil with lime.
- To keep it blue you would use aluminum sulfate.
- Purple blooms are usually the result of a more neutral soil pH.
This would be done in late winter or early spring.
Once a bloom has formed, you can not change or control the color. So, at this point you don’t need to do anything. However, as the bloom begins to decline (which they all do) the color may change to a lighter pink or blue. Some varieties will change to a light greenish or dusty pink color towards end of the bloom life.
As for fertilizer, feed them once or twice during the summer with a slow release fertilizer. I recommend something with a balance ratio like 10-10-10 or 14-14-14. You local garden center nursery will have this product.
Hope this information has been helpful. Please let me know if you need assistance with anything else.
Ask The Expert Reply: Jamie,
Thank you for answering back. My Hydrangeas are macrophylla. As for planting them in the ground, I can’t. I live in an apt complex, so they have to stay in pots. They are small now, as they get bigger I will plant them in larger pots until they get too big. Then I will give them away, and start all over again. I have two Hydrangeas that are a greenish color. When do I cut the blooms off? They look so healthy and beautiful I hate to cut them, but I want new blooms in the spring. You recommended fertilizer of 10-10-10 or 14-14-14, can you give me the brand name for both fertilizer and aluminum sulfate please?
Also, I have herbs growing too, like basil, thyme, flat leaf parsley, rosemary, onions chives, I’m having trouble finding plant food for them. I only seem to find plant that is mixed for flowers & vegetables. I don’t want chemcials in the plant food, can you recommend a brand to use please? Thank you for your help…
Flower Shop Network Plant Expert Reply: You don’t have to cut the blooms off until they are completely spent. The nice thing about hydrangeas is that the blooms last for a very long time. If you are keeping your plant in pots, you have two fertilizer options – water soluble and slow release granular.
I like to use Hi-yield or Peters water soluble fertilizer. When I use a slow-release granular, I like Osmocote. You can get these products at your local garden center or nursery. I assume when you say you don’t want chemicals in your fertilizer you mean an insecticide or fungicide. None of these fertilizes will have those types of chemicals.
Have a good day
