I have a lemon tree which I inherited from my father. It is about 40 years old and is a house plant most of the time. I live in Central Ontario, Canada where we only have a few months of nice weather suitable for outdoor growing of fruit trees. My tree had about 7 lemons in the spring which grew bigger than the ones you find in the store and were used up. Then again at the end of June, it flowered again. I now have about 7 more about the size of a golf ball and a couple larger. My question is how do I trim this tree. It is about 3 ft. high and never been trimmed. I try to tie it together a bit when it is not blooming or have fruit on it (which is rare). Also I happen to have a Mandarin Orange Tree (I believe it is Mandarin as my Dad planted it about 10 years ago (from seeds from the fruite) and the oranges are about the size of Mandarin Oranges. I tried a ripe fruit in the spring, but found it quite sour so I think it had not ripened. I now have about 5 small oranges ripe, but don't know anything about when these ripen. At least with a lemon, they get very yellow.
Re: Lime or Lemon? Wow! A 40-year old tree, never been pruned and it's only 3' tall? I'd like to know your secret to keeping it small yet healthy enough to bear fruit. I've pruned my trees a number of times but they keep reaching for the ceiling; it just seems to be their nature. As to your question, pruning is generally not recommended for citrus trees as it reduces fruit production. I would prune only if absolutely necessary in order to keep the size of the tree in check. Congratulations on getting your seed-grown 'orange' tree to fruit. Could the mandarins actually be calamondins? Calamondins have a sweet, edible peel but sour pulp. They grow to be the size of small mandarins if left on the tree long enough. I've had ones that are around 2" on my tree. If this is indeed a mandarin tree, it will require a relatively high number of heat units for the fruit to ripen and develop sweetness. This could be a problem for trees that spend a lot of time indoors. How long had the fruit been on the tree when you picked it?
My first taste of the orange was a few weeks after it was very orange. Now the orange has been "Orange" for about 1 1/2 mo. When you touch it, it feels like a mandarin in that the skin seems that there is a space between the skin and the actual fruit similar to a Mandarin.
There may not have been enough time spent on the tree with the one you sampled. Unfortunately the only way to tell if a fruit is ripe is to try it. I would leave the current batch on the tree longer but if the skin starts to look like it's drying or if the stem end starts to dry and go brown then it's definitely time to pick. An orange that had been on my tree for perhaps a year finally fell off; I had left it on the tree for too long but it was really sweet. Could you post pictures of the 'orange' tree, some with closeups of the leaves? I suggest you take pictures of the fruit the next time you harvest them as they may help you in identifying the variety. Slice the fruit in half so that the individual segments can be seen, like the pictures in the following link: Mandarin varieties in the UCR Citrus Variety Collection.
