A few weeks ago, while attending a function, a fellow attendee mentioned that he found a reference to maintaining a lawn in the February issue very useful. So, beginning with the lawn, the middle of April is the time to start applying a high nitrogen fertiliser at the rate of 30 grams per square metre.

This is followed by bi-weekly applications (or as instructed by the manufacturer of the fertiliser given on the bag), until the end of August, when nitrogen is reduced and phosphorous and potassium are increased. An example of a high nitrogen fertiliser would be 32-6-2 (NPK), which is 32 per cent nitrogen, 6pc phosphorous and 2pc potassium.

Lawns require high nitrogen to remain green, as frequent mowing causes the chemical to be lost in the grass clippings and is necessary for encouraging further growth activated by mowing. Lawns deficient in nitrogen are yellow-green in appearance and lack vigour.

Phosphorous encourages root development and potassium is essential for optimal growth, as well as disease resistance.

Fertiliser is best applied using a spreader, which ensures even distribution, thereby avoiding patchy growth and the risk of scorching or even killing the grass.

The machine is pushed up and down the lawn in strips in the same manner as mowing, taking care that the strips are not overlapped.

Even coverage is best achieved by dividing the fertiliser into two halves, applying one half in one direction and the other at right angles to the previous direction.

Other lawn-related tasks for April include mowing, of course, watering, edging and weeding - an ongoing task, especially during the summer months when weed growth is rapid.

This is in addition to pest and disease control - army worm being a particularly destructive pest as it eats the sward to the roots, leaving lawns entirely devoid of grass before moving on to other areas.

Migration can include crossing roads, when having devoured one stretch of grass, it crossed the road as a seething mass to attack the grass on the other side.

It's name probably derives from this characteristic, as moving like a marauding army.

Other pests are chafer grubs and cutworms, which chew their way through roots, leaving large areas of dead grass.

Deltamethrin and Diflubenzuron control army worn, while Gmma-HCH is effective against chafer grubs and cutworms.

Fungus diseases, such as Dollar Spot, Fusarium Patch and Snow Mould can be controlled using Vinclozolin, while Benodanil is effective against Fairy Rings.

At the same event, I was asked about edible flowers, with hibiscus and nasturtium coming to mind, both plants being in flower now.

There seems to be something of a craze for edible flowers at present, being used in soups, stews, salads and cakes as well as for garnishing dishes and also as infusions.

Certainly their bright colours are enlivening, making any dish sparkle with appeal.

The range of edible flowers is extensive and includes Arabian jasmine, the citrus family such as oranges and limes, dianthus, fuchsia, gladioli, impatiens, lemon verbena, passion flower, pomegranate, sunflower, viola, calendula, day lily, hollyhock and the snap dragon (otherwise known as antirrihinum).

On a cautionary note, the flowers must be undamaged, clean, free of insecticide and insect activity.

Stamens should be removed as pollen can have allergic effects.Ideally, edible flowers should be organically grown in one's own garden.

The benefits offered by the plant kingdom are truly amazing.

A few weeks ago, I read of the medicinal value of Tagetes erecta - the African marigold, incidentally another plant with edible flowers.

However, its flowers contain meso-zeaxanthin, a substance medical research has found that reverses macular degeneration, which is an age-related condition that affects half the cases of blindness in the UK.

Another plant of medicinal value is the salt bush (Atriplex halimus), found in many Bahraini gardens.

Its leaves, as an infusion, help in controlling blood sugar - hence it is of enormous benefit to diabetics.

The seeds of Moringa oleifera, the horseradish tree, have the ability to purify water.

The most amazing aspect of the plant kingdom for me is that it is our primary source of oxygen, and equally amazing is that few know this and most of those who do take it for granted. More on this subject in a future issue.

During a recent visit to one of the new island developments, I noted that trees and shrubs planted only last year were exhibiting signs of nutrient deficiency.

Fertiliser quickly degrades and disappears from the soil here in Bahrain. It is therefore necessary to apply it at regular intervals.

The usual method is to apply fertiliser by hand around the base of the plant.

This works fine in countries with regular rainfall, when the fertiliser is evenly wetted by the rain and hence passes evenly down to the roots.

In Bahrain, this method does not work so well, especially in the case of an irrigation system in which emitters are positioned at a single point near the plant.

Fertiliser will only percolate down from that point to a particular aspect of the root system, leaving much of the rest of the root area without nourishment.

This is evident in shrubs when growth is lopsided.

An alternative would be to introduce multi-emitters to each plant or create a matrix of mutually supportive emitters, all of which would not necessarily be near a plant.

This allows for a greater area to be irrigated and as a consequence a greater area of the root zone to receive dissolved nutrients.

Fertiliser can be introduced to an irrigation system in liquid form by means of injection with the dissolved nutrients eventually reaching the roots as the irrigation water passes through the soil horizon.

When this method is used, it is essential that emitters are cleaned regularly as they can become blocked with congealed fertiliser.

Another method, and this is more applicable to the small garden, is to apply fertiliser around the base of the plant and fork it into the top 100mm of soil and follow with copious watering to ensure that the entire root zone benefits.

On the same development certain trees appeared to be having a hard time getting established, Cassia fistula, the Indian laburnum, in particular.

In the event, one of them was lifted and found to have developed no roots at all since being planted.

Examination of the roots found traces of a gel, a moisture retention substance that had been added to the soilless compost used in transporting the trees from India.

This may have caused an adverse reaction between it and the chemicals used in the planting medium, which inhibited root growth.

Another factor could have been the constant offshore wind, though having said that Cassia fistula recently planted on another coastal development are doing well. Cassia fistula is a glorious sight in flower.

Another tree on the same development that appeared to be suffering was Millingtonia hortensis, the Indian cork tree or tree jasmine.

I concluded that wind was a contributing factor, the other being the recent fluctuating temperature.

While new shoots appeared encouraged by a warm spell, they were knocked back by an ensuing cool spell accompanied by a cutting wind.

With the warmer weather on its way, though, I expect them to flourish.

Millingtonia is an elegant tree of narrow habit and bears panicles of intensely fragrant pure white flowers that clothe the entire tree, making it a splendid and welcome addition to any garden.

Finishing on a medicinal note, both Cassia fistula and Millingtonia hortensis have great value in this area.

The flowers of Cassia fistula have been found to contain antioxidant properties.

The leaves are useful in relieving irritation of the skin and alleviating swellings and pains, while the pulp is a safe and mild purgative, in addition to the root that is useful for relieving fever.

The dried flowers of Millingtonia serve as a bronchodilator, the root a lung tonic and the leaves have anti-microbial properties. One's garden is really a green pharmacy.