Q. There seem to be different types and sizes of terracotta pots in relation to the kind of plants they are suitable for. Please guide on how to choose the right pot for any plant.

A. Generally speaking, a wide, shallow pot is suitable for a shallow rooted, low-growing, spreading plant which doesn’t require much water or nourishment — creeping thyme and small succulents being prime examples. A tall, cylindrical, deep pot is designed to be home to a plant that is tall and slim or perhaps for an annual climber such as ipomea/morning glory vine. A very large, deep, wide pot is intended for something like a small to medium size shrub, such as a rose bush or for some other plant that requires plenty of root space and has lots of top growth, perhaps a frangipani. Pots are all about root space and balance: if a plant with lots of lush growth is put into a slim pot it is liable to become top heavy and will easily fall or be blown over. A plant expected to attain a height of 6ft needs to have its roots in at least 3ft of soil; a plant growing just 6 inches tall requires at least a 3-inch depth of soil and so on. Envisage the shape and size of a mature plant, keeping in mind that its roots are liable to need soil to the depth of at least half, preferably more, of the plant height and you will get the idea.

Q. My ladyfinger (bhindi) plant started fruiting three months ago. Recently, instead of being yellow, the flowers turned brown and didn’t set fruit. They are being grown in a pot on my rooftop in Karachi where temperatures can reach 40 -50C in summer.

A. Your plant is quite literally cooking! An exposed rooftop in Karachi, in summer, is no place for any plant to be. To get the best out of your rooftop garden you need to install some kind of summer shade, securely fixed green netting being ideal.

All your gardening queries answered here

Q. I am an 11-year-old boy from Islamabad and am a wildlife enthusiast, birdwatcher and hiker. I read your gardening column every weekend. In a recently published column, you mention lantana as being a garden plant. According to my understanding, it is a toxic bush introduced in Pakistan when it was brought from Central America ‘accidentally’. Not only has it been introduced in Pakistan, but it has spread throughout the tropical regions of the world and is among the six most invasive plant species in the world. It has taken over the natural vegetation of the Potohar Plateau and approximately 15 percent of the Margalla Hills National Park has been taken over by this plant. It fiercely competes with native plants (kachnar, Chir Pine on the higher slopes). It is toxic to livestock and humans. So please explain why you are calling it a garden plant.

A. Hat’s off to you young man! I am impressed that you have studied this subject and hope you continue to do so. In my own defence: I have written about this toxic, invasive species in the past and have also requested people not to grow it in their gardens. The reality though is that they do grow it and are unlikely to stop, and plant nurseries are not going to stop selling it either. Therefore, when asked a question about cultivating lantana, much as it goes against the grain, I feel honour-bound to answer.

Q. What is the best time to water lawn grass and fruit trees in the summer season? My gardener believes that water should not be given during daytime and that the best time is before sunset. What is your opinion? I reside in Islamabad.

A. Your gardener is 100 percent correct.

Q. I really need help to identify dandelions. Do they grow in Islamabad? And if they do, will they look exactly like the dandelions in the West?

A. Dandelions, botanically named taraxacum officinale, are common in Islamabad greenbelts during the spring. Because of soil and climatic conditions, plants here tend to be somewhat smaller than those found growing in temperate regions of the northern hemisphere but, in all other aspects, they are exactly the same.

Q. My chikoo tree is nine years old. It started fruiting two years ago but this year it didn’t produce any fruit. Please help me regarding this issue.

A. The tree may be lacking nutrition. Contrary to popular belief, chikoo trees are heavy feeders and, without enough nourishment, fruit does not form. Feed your tree with fully rotted down, preferably organic, animal manure once every four months. Ensure that it is irrigated at least once a week from spring to the end of summer, and once every two weeks in the winter, unless there is seasonal rain of course.

Q. All trees planted in public parks, on sidewalks and road dividers in Karachi are watered with raw sewage. I am curious to know whether these trees will provide the same benefits to the environment as those that are watered with clean water.

A. The trees that you mention are watered with treated, not raw, sewage water. Either way though, healthy trees benefit the environment irrespective of the kind of water used to irrigate them. There is no difference at all.

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, August 1st, 2021