I have had a few miniature pommegranates for several years. They are very dificult to cultivate and i thought i would share some solutions to thier health and vigor.
I have moved towards using fired clay based soils this year. The nutrient requirements in this medium have suprised me. They require far more than I had expected. Now that i have the big pines under control in this medium i turned my attention to some really sickly pomegranates in the same medium. weekly fertiliser wasnt having much impact at all.
In some older translated japanese bonsai books I have found a little advice about them. They advise deaper pots to suit the habit of the root system - and also note that they are heavy feeders. Any fruiting or flowering plant requires a lot of food during its productive season - my experience with the calamondon has taught me about this - and i also have a huge chilli harvest which uses vast quantities of feed to get its large yield.
A single overstrength dose of fertiliser every 10 days had almost no impact. Not on pines or citrus and certainly not on the pommegranates. The chillies and fruit now get fed every 2 days at normal strength. This wasnt enough for the pommegranate. I think part of this is due to the medium they are planted in - akadama is much more forgiving and seems to retain more nutrients.
I used Canna on the pines with good results. But its for vegetative growth and not flowers or fruit. It did revive the pomegranates and bring them back to reasonable health. The extra gogo im hoping will come from the Tomorite which has the better balance of nutrients for flowering plants. My chillies and tomotoes love the stuff - and the calamondon seems to be doing well on it too.
As i increased the frequency of fertilisation i became annoyed with the ammount of waste. For the calamondon i tollerate this as i only fertiliser every second day.
I use nutrients and equipment from the hydroponics industry. So i decided to grow the pomegranates on a home made ebb and flow hydroponic method. Simply I keep 5 litres of nutrient solution in a bucket. The pots are submerged into this solution twice a day or if the pot is very light from being dry.
This home made ebb and flow hydroponic setup had brought lush growth to the pommegrantes at last. I use the solution for about a week and then dump it on the beeches and hawthorns. So there is little waste of nutrient anymore.
Next year they will need a different soil to thrive - but for now they are well again.
Ebb and Flow