Plant Doctor Archive

Poor fruit on mandarin

Question WE have an eight-year-old mandarin tree (I think it is ‘Clementine’) which is growing beautifully and each year is covered in fruit which looks sensational but is virtually inedible. The problem is that the mandarins never sweeten, no matter how long we leave them, and of course, after a few months, they eventually dry out. We diligently sprinkle citrus fruit fertiliser around the drip line, plus Epsom salts, and have kept up with the watering in summer months. The tree is planted in the lawn with no cultivated ground below, and we wonder if this is causing the problem, or is it simply that we have planted a dud? It was a gift for my 50th birthday and I would really like to persevere if you think there is any hope. We love mandarins and totally resent having to buy sweet ones from the supermarket while our tree taunts us with its laden branches.

Answer  CITRUS are great fruiting trees to have in a garden, especially when they give wonderful rewards of juicy fruit to be used in many different ways. However, it’s a real nuisance when citrus trees produce fruit that is tasteless and dry.

Your problem could be irregular watering. Try covering the area under the tree with mulch. Put down bark or wood chips to increase the amount of moisture that the soil can retain. Water well before putting the layer of mulch down.

Feed with citrus fertiliser every 3–4 months. Use Yates Gro-Plus Citrus food and water in well around the drip line. Be aware that sometimes, too much fertiliser can cause the fruit to drop or be dry.

Try using some Sulphate of Potash around the tree as well — this helps to encourage good fruiting.

Epsom Salts are used to correct any magnesium deficiencies that the plant may have.

If your tree still refuses to perform, perhaps you could plant another variety elsewhere. Then enjoy your birthday gift for its ornamental qualities!

Weekend Gardener, Issue 104, 2002, Page 20