July 03, 2008

Q I have recently purchased some dahlia tubers from abroad and they are packed in their original perforated plastic packing. Is it advisable to plant these tubers in the soil or in pots placed in a shaded location for the next few months, to protect them from being damaged by the scorching heat prevalent in Lahore?

A The tubers should be planted, in pots, in the shade as soon as possible. If left inside their packing they will quickly begin to sweat and rot even though the plastic is perforated. Ideally plant them in 14 – 16-inch pots or even 24-inch pots if the tubers are large. Ensure that the drainage hole in the base of the pot is kept clear by putting a layer of broken crocks inside the base to facilitate drainage as dahlias will not tolerate extremely damp conditions.

Soil should be reasonably rich with old, well rotted organic manure/compost mixed in. Plant the tubers so that they have three to four inches of soil on top of them. Keep them in a location which receives sun from around dawn to 11 a.m. only, if at all possible, or in a location which receives sunlight from early to mid afternoon until sunset. It is important to keep them totally out of the midday sun at this extremely hot time of year.

As you mentioned dahlias tend to be at their best during spring in Lahore but, if they are shaded from direct sunlight as detailed above, they can flower for a much longer period of time. I presume, due to the packaging details, that the tubers have been imported from either Europe or America as those coming in to Pakistan from India are not so professionally packed but do keep your eyes open for the Indian ones as some of them are absolutely stunning.

Q A year ago I read something about yarrow plants and your experience of their use in Pakistan in raita. Could you please explain yarrow plants and the colour of their flowers? I regularly read your articles here in New Jersey.

A The species of yarrow plant widely used in the northern regions of Pakistan is the indigenous wild achillea millefolium which has white or pink tinged flowers. Cultivated forms of the same species have flowers in pink, rose, purple, grey, cream, yellow, cerise, apricot, bronze, lilac and orange all of which are used in the same way. Recommended varieties are A. millefolium summer pastels, Colorado, debutant, cerise queen and cassis.

Yarrows have numerous uses, culinary, medicinal and the plants can be steeped in water to obtain a very good liquid fertiliser with a high copper content as required by certain other species of plants. Used in companion planting it is claimed that yarrows improve the health and vigour of nearby plants and also assist them in fighting pests and disease. A useful species to have around!

Q My problem is that my garden plants have more vegetative growth than floral growth. I have planted zinnias which have more leaves then flowers. It is the same case with raat-ki-rani and motia. Please suggest some remedy.

A Whoops! Sounds like a typical case of over feeding. If soil is too rich, hence too well fed, species such as zinnias will grow like crazy and almost forget to bloom. This can also happen if they are over watered. Zinnias flower best in medium to poor soil conditions. As there isn’t much you can do about their soil right now you could try cutting back on watering and do not, under any circumstances, give them anything else to eat!

Raat-ki-rani and motia flower best in medium soil conditions as rich soil encourages them to put on an astronomical amount of green growth minus flowers. The latter two, being perennial shrubs/creepers should be lightly pruned during December or January to help them produce flowers in the next season.

Don’t kill and suffocate your plants with too much kindness please as they don’t appreciate it.

Q Can you please tell me what ‘ohia lehua’ and white ginger are called in Urdu as I would like to purchase these species of plants for my garden in Karachi.

A I would presume that white ginger is simply safaid adrak in Urdu but as both this and the other species you name are from Hawaii and were only introduced in to Pakistan very recently and as far as I am aware, there isn’t yet an Urdu name for them. You may be able to track plants down in a specialist nursery but I suspect that those already in cultivation here were brought in privately although I may be wrong. Good luck in tracking them down though as they really are beautiful flowering plants.

Q I am a student of Agricultural Entomology, fourth year B.Sc. degree at the college of Agriculture in Quetta. I need material or notes about pesticides and their application on agricultural insect pests. Is there any type of website which provides this information?

A I get an increasing number of questions from both agricultural and horticultural students and am quite dismayed by some of the things asked and this goes for your question, too. As a student, a major part of your knowledge will be obtained by conducting your own research and from asking your teaching professors for relevant information.

As you have computer access you can, presumably, look for websites. But there have recently been quite a number of cases where professors and students have both been caught plagiarising other peoples work downloaded from the Internet and I sincerely hope that you aren’t about to fall in to this trap.

Q Last year my peach and nectarine trees were badly affected by fire blight. This year small leaves and dark, marble sized fruit have appeared and they look pathetic! Should I wait for another year for them to pick up or should I remove them at the end of the fruiting season and plant some other trees in their place.

A Please remove the infected trees from your garden as soon as possible as the spores of fire blight will still be there and possibly in the ground beneath them, too. Remove, burn if possible, every single trunk, branch, twig, leaf and piece of root you can manage and then sterilise the soil areas with a flame gun if possible. Do this well before even thinking of planting any new trees.

In some countries fire blight is a recognised disease and infected trees are destroyed by the concerned governments. The longer a fire blighted tree is allowed to stand in place the higher the chance of the wind borne spores being carried to other susceptible tree species in the vicinity.

• Correction: A reader in Karachi kindly pointed out an error in a recent article where I wrongly named flame of the forest as being botanically called ‘poinciana regia’ when it is, in fact, ‘butea monosperma’. ‘Poinciana regia’ is gul muhor. My apologies for this error and my thanks to the gentleman who submitted the correction.

Send your gardening queries to zahrahnasir@hotmail.com. Answers to selected questions will appear in a future issue of ‘The Review’. This will take time. The writer will not respond directly by e-mail.