Acacia Tree Leafs Falling Off

Question

Dear All, I brought some acacia seeds from Zambia (exact species unknown).I grew 2 x plants that are 9 months old now. At first germinated individually then put together in the same pot (~ 2 months aft. germination). One was sick almost from the start the other was beautiful until ~ 1 month ago. She had got the symptoms on the lower leaves for quite long time but seemed not to be bothered. It took the disease(?) ~2-3wks to strip her of the leaves so they both look the same now. Even the fresh green leaves fall off when plant is flicked. I don’t think that the conditions are adverse as one of them had been OK and happy. I keep them both on the southern window sill and water quite generous but not often. Maybe every 2 months. I live in Europe so the temperature they are exposed to are nothing close to African ones. I winter the temp. does not go below 15C. Have you got any idea what is killing my plants? Best wishes Michal

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Answer 1

They may need more water. You might try weekly neem oil treatments. I can't see powdery mildew in these photos, but it's a possibility. There may be other things plaguing your little trees, but neem oil takes care of a lot. Another thing you could try is feeding them with orchid fertilizer, which is recommended for their first year of growth, or fish fertilizer or compost tea. They might just be hungry. Here are a couple of articles that may help:
https://www.gardeningknowhow.com/ornamental/trees/acacia/acacia-tree-types.htm
https://www.gardeningknowhow.com/ornamental/trees/acacia/acacia-seed-propagation.htm