Conocarpus trees
Q. I want to know about Conocarpus trees which, I understand, are native to the US. Some people have a negative response about it, others are positive. Conocarpus has been planted in Karachi in abundance because it is supposedly requires little water and maintenance, and grows quickly to provide greenery. From what I read, the negative aspects are that no birds come to this tree, that it causes less rainfall and causes allergies similar to the pollen allergies causes by paper mulberry trees in Islamabad. Is all this true or just exaggerated, illogical myth?
A. The concerns about massive Conocarpus plantation in Karachi are, if anything, underplayed. This imported tree species is a huge problem on a number of fronts: 1) It flowers twice a year, spring and autumn, and has the potential to be a huge problem for those suffering from pollen allergies. 2) It does not provide any food or sustenance for indigenous birds, bees, butterflies and other insects. 3) Its root system is such that it is highly damaging for road and pavement surfaces, underground service pipes, and house and wall foundations. 4) Whilst drought-tolerant once established, the roots of Conocarpus trees naturally seek out sub-soil water and use it, thus reducing the water table even further: in this respect it is just as bad as the previously-introduced problematic Eucalyptus.
Large-scale planting of just one tree species, irrespective of the species, is detrimental to the environment as a whole. It would be far more sensible, certainly environmentally so, to plant a wide mixture of indigenous trees in the city rather than just an imported one with massive problems attached. I hope this clarifies the situation for you.
All your gardening queries answered
Q. Which fruits can be grown in pots in Mardan and how should they be cared for?
A. A very wide range of fruiting trees, bushes, climbers and plants have the potential to do well in Mardan as long as the soil is of good quality, irrigation regular and pots/containers are suitable in size. It is advisable to select small/dwarf varieties of trees. Some of which you may like to try are: peach, nectarine, pomegranate, plum, pear, orange, lemon, grapefruit, apple, apricot, loquat and cherry. Fruit bushes, such as blueberries, raspberries, gooseberries, blackberries, blackcurrant, red currant and white currant are possible, provided perfect soil conditions are supplied. Climbers that do well in pots are passion fruit and kiwi fruit, while fruit plants such as pineapples, Chinese gooseberries, strawberries, plus purely seasonal sweet melons and water melons are also possible to grow. It is important to feed them, preferably throughout the growing season, with organic compost/manure or liquid fertiliser, on a monthly basis.
Q. I understand that Epsom salts can be used to improve plant health. What amount should be used per plant and how often should it be given?
A. This natural substance is, amongst other things, high in magnesium sulphate and sulphur and it is an excellent, all round, general plant tonic. Dissolve one tablespoon full in approximately four litres of water and use either as a foliar spray or watered directly onto the soil at the base of your plants. Using Epsom salts once a month is highly beneficial.