Q. Mealybugs are a major problem on my pot plants on my apartment balcony. I have tried every method I can think of to get rid of them, including organic pesticide and even netting the pots, but nothing seems to keep them at bay. Please tell me an effective solution.

A. Mealybugs are notoriously difficult to eradicate as their eggs can — and do — remain in the soil from season to season. You need to replace all the soil in your pots, disposing of this probably infected soil in bags, in the garbage bin and sterilise your plant pots before reusing them. Additionally, before repotting your plants in new soil and clean pots, carefully remove as much soil as possible from around their roots, swishing them around in a bucket of warm, soapy water, prior to putting them back in their pots. Additionally, and also before repotting, hand-pick off any mealy bugs you can see on the plants and, finally, spray the plants with warm, soapy water mixed with neem oil at a ratio of three teaspoons neem oil to one litre water. You may loose some plants as a result of this cleaning up process but those that remain should thrive. It would be wise to completely scrub down and disinfect the balcony too.

Q. I am trying to start a plantation drive, along with my fellow students, first in our university (NED) and later in other areas of city. I researched online to shortlist some trees that require less water, produce more oxygen, grow quickly and look beautiful. In terms of beauty, I shortlisted maple and tricolour beech but apparently Karachi’s weather is not ideal for these. The other options are neem and Douglas fir. Kindly suggest some trees, either from those I have mentioned or others that can survive the weather here and provide maximum benefits in terms of oxygen and shade.

A. Neem is the only tree you have mentioned which is suitable for your well-intentioned project. Others you may like to consider are these fast growing, shade creating, species: ‘Albizzia lebbek’ — Sirus, ‘Erythrina indica’ — Indian coral tree, ‘Melia azadarach’ — Persian lilac, ‘Pithelocobium saman’ — Rain tree, ‘Ficus indica’ — Banyan, ‘Ficus religiosa’ — Peepul, ‘Ficus infectoria’ — Pakar, ‘Tamarind indica’ — Imli and ‘Terminalia catappa’ — Badam. You have plenty of time to organise a source of saplings before the next tree planting season, which is during the monsoons. It is hoped that, along with organising initial planting, that follow-up watering and essential maintenance are ensured as well. Simply planting saplings and leaving their survival to chance is a complete waste of time and resources. Wishing you and your team all the very best. If you have any further queries, please do not hesitate to get back in touch.

All your gardening queries answered here

Q. I have twice planted lychee trees at my home in Peshawar but, after some time, they died. I am very concerned about this but would like to try again. Can you please give advice?

A. Not having any knowledge of how/why the trees died makes it rather difficult to give correct advice. Generally speaking, before planting any sapling, it is essential to pay attention to soil preparation and drainage issues. The planting hole should be at least twice as deep and twice as wide as the roots of the sapling. Remove stones/weeds and other debris from soil excavated from the planting hole. Then create a soil mix with 30 percent old, well-rotted, preferably organic manure, 50 percent soil and 20 percent river sand. Half fill the planting hole with this mix and then water it to settle the soil mix. Next, carefully insert the sapling, spreading its roots out in a balanced manner and, a bit at a time, infill with the rest of the soil mix. The base of the sapling trunk should be level with the soil surface and not below or above it. Water well and keep watered — watering deeply twice a week — until the sapling is visibly happy, which may take three to four months. The next suitable planting time is during the monsoons, so please wait until then before trying again.

Q. The leaves of my tomato plants growing on the balcony of my flat in Lahore had white squiggly lines on them. So I treated the plant by using organic pesticide spray and pruned away the damaged branches. However, now the plants flower but they wither and die instead of fruiting. What must I do?

A. The white squiggly lines are caused by leaf miners tunnelling inside the leaves. If the infestation is mild, squashing these bugs inside the leaves can resolve the problem, as can removing and sensibly disposing of infested leaves. Depending which pesticide you sprayed with, it is possible that pesticide residue remains on the plants and is preventing necessary pollinators, such as bees and other beneficial insects, from pollinating the flowers. Unpollinated blossoms quickly wither up and drop off. I suggest that, hard as it may be, you remove existing tomato plants, renew the soil/compost and start again. If you sow seeds of cherry tomatoes, or another quick-to-ripen variety, you still have time to get a decent crop before winter arrives.

Q. How can I grow a lemon tree in Karachi? I have tried several times but failed.

A. Try Chinese lemon/lime. These are hardier than other varieties and do quite well in Karachi.

Q. I live in an apartment near Seaview and have a whole terrace that I want to fill with flowers and plants. Which fragrant plants do you recommend for this location?

A.  Please resubmit your question with the addition of the following, essential information: How close to the sea is your apartment? Does it face the sea or is it protected from the sea breeze? How many hours of sunlight does it get each day? Thank you.

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, May 30th, 2021