Lost Longans

by Bob Cannon

Misplaced plants, tucked in an out of the way corner can be forgotten. Is rarely deliberate, but as the year progresses that set aside plant is thought about less and less, forgotten. Even if it was a sought after acquisition. Sometimes, as in the case of many palm and cycad seeds, when rediscovered the grower is presented a prize, a pot of happily growing young plants. Sometimes all you find is an empty pot and label. Most of the time you find a plant hanging on, growing little if at all. Such plants are likely to be pot bound, or to have lost most of the soil originally in the pot. In areas of heavy growth, frequently roots from other plants have entered the pot, through the drainage holes, to steal what nutrients they can.

I recently 'discovered' a pair of longans, Dimocarpus longan 'Kohala', that I had airlayered over two years ago. When I first potted them up they were placed where I thought they would be OK but a weedy plant hid them while I was not looking. When I found them they were little larger than when cut from the parent tree, one was somewhat smaller. Both were firmly attached to the ground, my examination showed roots from nearby plants growing through the drainage holes into the pots. Both had also developed 'companion' plants - one a Boston fern the other a seedling longan. Figures 1, 2.

1. Dimocarpus longan 'Kohala' in this figure the smaller pots have been placed into the destination pots to show the increase in size.

2. You can see that both pots have volunteer plants as well as the original longan. Tag and ribbon on the plant on the left are markers as to layering methods.

When I tamped the plants out of their pots they were very light. Examination of the roots showed many small, feeder type roots but no large roots. The Boston fern and roots entering the pots from outside were removed. The remaining roots were loosened some, but care was taken not to overly disturb them. The seedling longan was left in the pot. Should it show positive seedling vigor I'll approach graft it into the layered plant so that a more vigorous root system is obtained. (This is a trick Dr. Richard Campbell taught me (in reference to recalcitrant jakfruit)).

On the right you can see a repotted longan with the remaining seedling. The new pots provide 1 1/2 to 2 inches more diameter and about 4 inches more in depth. Fertilizer has been added and the soil tamped with the tool shown. There is room to add an inch or so more soil, which will be done before watering. The home made Plexiglas tool is a potting aid I developed that I use as a dibble. Besides the bright colour and wrist strap, to prevent loss, it is marked on one edge in 1/2 inch increments. The other edge is beveled to assist in detaching clinging roots from the insides of pots.

3. Unpotted and ready for removal of surface 'leaves' and potting up to a larger size.

4. In the new pot with most of the new soil added. Seedling longan on left, orange 'dibble' on right.

Both plants in new pots, the one on the left, fig. 5, has had dead wood removed. Once in active growth the stub will be reduced further. The pots will be watered and placed into 30 percent shade until vigorously growing. Next season they will be ready for planting into the landscape or repotting once again. Since I have lost plants due to disturbing the roots I will use care while these plants recover from their neglect.

5. In new pots and ready for watering.

6. Callus formed at top of layering wound, (green colour is lichen).

One of the plants has developed callus above the layering wound, Fig. 6. I've seen this a few times before and it does not seem to cause any problems for the young plant. The main lesson is that if you lose track of one of your fruit plants there is a good chance that it can be rehabilitated once found.

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Updated 8 December 2008