7yr old Mimosa/Acacia not flowering

Mariko

I bought baby mimosa (a bout a foot high) 7 years ago, and Now in 45L pot and 8feet high. I have not pruned but every year, I have only 1 or 2 flower buds forms. My neighbour has 7 feet high in pot and full of flowers. Why mine does not? I have placed this pot in south/east facing walled garden. 

Obelixx

I have 2 mature trees inherited with this garden.  They flower profusley every year but then they are planted in fertile soil and get weather that suits their needs.

Can you tell us where you are, what compost you have used for planting and whether or not you feed it at all?

Mariko

We live in west dorset, and I used multi purpose garden compost from local farm shop own brand. I only repotted last year to this bigger pot. Soil never dried up as we are always wet.  I have fed tomato feed during summer every few weeks. This year all I can see is just one tiny cluster of flower bus i whole tree! last year we only had 3 flowers...

Obelixx

I think multi-purpose is too claggy for this tree.   They like a loamy soil and good drainage.  They also like to be a bit on the acid side.

I would re-pot using John Innes no 3 which is loam based so will give good drainage.    Mine are in the ground in loamy soil and had no rain from mid June to October apart from a couple of neglible showers in September and they did not wilt, although being old, they will have their roots deep down to get available moisture.

I think you should then top dress every spring with and ericaceous compost and some slow release food for ericaceous plants.   If your tap water is at all alkaline, use a liquid feed with equestered or chelated iron to make sure the calcium doesn't lock up the iron and magnesium that the tree needs.  You can also use rain water.