Q. I had two 30-foot tall sheesham trees, which I grew in front of my house in Rawalpindi for shade. One died last year and the second died recently. I replaced the first one with a pecan tree but it quickly lost its leaves and died as well. I believe that the problem is a tree-killing fungus in the soil. The trunks and most of the sheesham tree roots have been removed to a depth of approximately three feet. I need advice on what to do next so that the saplings I plant to replace previous losses will survive and grow into healthy trees. Space is limited and I do not have the option of planting trees elsewhere.

A. Oh dear! You certainly do have a problem as, I suspect you already know this, the culprit is likely to be Phytophthora spp. a lethal fungal infection of the soil which is all too common in and around Rawalpindi and Islamabad. The only hope in controlling the infection lies in greatly improving both drainage and soil structure which may not be simple for you to do. Removing soil to a depth of three feet is not enough, as there will be lots of tree roots still in the ground: the trees having been 30 feet tall, getting all the roots out is impossible. There is no successful chemical control. As it stands, whatever tree you plant in that location is going to suffer the same fate as its predecessors — unless you are prepared to leave the spot vacant for seven to nine years before trying again. I realise that this leaves you without trees and without shade but all I can think of for you to plant immediately is ultra-fast growing ornamental bamboo: at least you will have privacy and a measure of shade which is better than being totally without.

Q. How can I tell if I am watering the plants in pots and those growing in the ground too much?

Gardening is a tricky hobby; everything has to be right to have healthy plants

A. The signs for over-watering are: soil surface may develop greenish mould, be visibly wet at all times, plant leaves may droop and plant roots may rot away.

Q. When making liquid fertiliser is it necessary to use all the ingredients mentioned in your article of October 16, 2016 or can I use just some of them?

A. There is no hard and fast rule so simply utilise what you have on hand.

Q. I have an eight-year-old lychee tree which doesn’t fruit. Due to a high wall behind it, it doesn’t get winter sunshine but now it is tall enough that the top portion of the tree can enjoy some sun. Will this help it to fruit?

A. Unfortunately you have omitted to give your location which means that your question cannot be answered with any certainty. Weather/soil conditions vary tremendously throughout the length and breadth of the country and these affect plant growth and fruiting capabilities. Basically though, if you are in Karachi, the tree is unlikely to fruit at all as lychees need more winter cold than is usual in Karachi. If in Lahore or Islamabad/Rawalpindi, if the tree is a grafted one, it should fruit in time — lychees normally begin fruiting at an age of five to 10 years. If it is seed grown, it may never fruit. Sorry, but as the location is not given I cannot be more specific.

Q. Can I grow an avocado tree in Clifton, Karachi? If so, then how?

A. Avocado trees are unlikely to succeed in the Karachi climate. Sorry!

Q. The leaves and flower buds of my roses keep drying out and falling off. There seems to be fine spider-web on the plants. Is this the cause and how to remedy it?

A. Your roses are infested with spider mites of some kind. Spray them — make sure to spray underneath them as well as on top — in an evening with one of the following: a) warm soapy water b) garlic water c) hell-fire spray d) neem spray. Spray each evening for three or four days, and remove all infected leaves/buds from the plants and from the soil surface around them, disposing of this detritus well away from your garden. Repeat the treatment after 10 days and again after another 10 days by which time all traces of the pests should have gone. The plants should then begin to put on new, healthy growth. Keep an eye on them and immediately spray again if pests reappear.

Q. What are the rules for successful seed sowing?

A. Keep seed trays/pots 100 percent clean. Use the best quality soil/compost mix possible. Ensure that drainage is good. Do not over water. Do not sow seedlings too close or too deep. Follow instructions for sowing individual seed varieties to the letter.

Q. I reside in Lahore and want to grow Moringa oleifera in my garden. Can this highly medicinal tree, called Drumstick tree and Horseradish tree in English and Sohanjna, sahajna or munaga in Urdu, be grown here and where can I find a sapling?

A. Moringa oleifera loves it in and around Lahore. Check local nurseries for saplings or search the internet for a local source of seeds.

Please continue sending your gardening queries to zahrahnasir@hotmail.com. Remember to include your location. The writer does not respond directly by email. Emails with attachments will not be opened.

Published in Dawn, EOS, March 12th, 2017