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Tall bearded Iris by Malcolm Campbell

Tall bearded Irises are evergreen herbaceous plants with swollen rhizomes that develop at the surface, as opposed to the bulbous Iris species that seasonally produce dormant bulbs.

The tall bearded varieties and cultivars flower from Mid September in the arid areas, or October in the South through to early December. They are really at their peak for about six weeks in October and November, when a tall vase in-doors will be crammed with a profusion of blooms from even the smallest patch.

Their leaves grow from 600mm tall to just over a metre and have flowers that are up to 150mm wide, with most cultivars having two or three blooms per spike.

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They are very forgiving plants and actually thrive on neglect. That is providing you had sufficient intuition or experience to plant them in a good spot originally. While they will grow almost anywhere even in shade, they will flower best on well drained loamy soils in full sun. Their grey leaves would indicate to the keen plantsperson that they prefer full sun, which they certainly do.

Soils

Now if you are saddled with a heavy cracking clay, you will already know that gardening is an ordeal on such soils, so you will be familiar with using gypsum to improve soils structure, that makes the soil more free draining.

It works surprisingly fast too, so that even after a single day you will notice that water drains away rather than lies around. Quite simply gypsum is calcium sulphate, has very little effect on the pH of the soil which determines the acidity or alkalinity and is only slightly soluble in water. It's fairly cheap and can be used in large quantities in the range of 250mgs to one kilogram per square metre or from 2.5 tonnes to 10 tonnes per hectare on the broadacre, however start at 100mgs per square metre in the garden, which is about a decent hand-full. You can use garden lime to improve soil structure too, but only use lime on acidic soils with an acidity of of less than pH5. Either way gypsum can be used on all soils with good effect, since it leaves the soil pH neutral or rather the same as it was prior to being treated.

Flowers

The Iris reputedly comes in the widest colour range and combination of colours of any genera of plants in cultivation.

They have the form of the orchid the vigour of weeds and the beauty of... well irises. They make wonderful long-lasting cut flowers and if you deck the mantle piece with flowers you may choose to grow the paler 'designer' colours, rather than the intense black or maroon colours. When cut as buds, they continue to open just like Gladiolus, so that if a hail storm threatens you can dash out and cut all the buds to save then from being decimated.

Planting and lifting

While they can be lifted at any time of the year to divide and transplant, which is good news if you move house frequently, they are best lifted to divide after flowering from December to March. That is not to say that they need to be lifted every year because they don't, but after three or four years you will find the clumps get a bit large so flower quality and quantity deteriorates. That's when you should lift them and renovate the soil, by adding some old organic compost. It's through this compost base that the fertilizer exchange takes place. Think of it as the sponge through which the Iris feeds, because no matter what fertilizer you use it will only be taken up by the plants in a solution and so if the compost prevents the soil from drying out that conduit for feeding is always open. These Iris like a pretty dry soil dry and the compost makes sure that they can still feed even when its quite dry.

When planting out newly purchased rhizomes, they will have a few leaves that have been cut back pretty hard and a few roots. The rhizome is planted flat and the top third, left out of the soil. This is most important or else the rhizome will rot. Did a planting hole at least 300mm deep and back-fill with friable sandy loam and old compost, together with some blood and bone or human hair, leather savings and a little 'Complete D' or superphosphate. The hair and leather breaks down into nitrogen and sulphur very slowly and the superphosphate is quickly available to swell the rhizome that pushes the flowers along. For exhibition quality blooms fortnightly watering with water-soluble fertilizers that have a high potassium ratio, will return the best quality flowers, but fertilize sparingly because Iris are not gross feeders. Incidentally the proprietary tomato fertilizers are quite good for Iris, since they are usually high in potassium sulphate. Fertilize after flowering too, by lightly working the fertilizer into the soil, being careful not to disturb the shallow roots. Keep all old leaves removed or else the shading can cause some ideal slug and snail habitats. Apart from that they are fairly hardy plants and not generally prone to disease, unless over-watered.

In arid areas, like Mildura and Broken Hill, water at night to reduce the evaporation and soil-salt buildup, while in cooler areas like Melbourne it's best to water early morning so that the plants can enjoy the warmth of the day and not have a cool moist micro-climate in which some fungal diseases are known to spread at night.

Varieties

Most gardeners select their Irises for blooms to cut and display, so the colours usually decide what gets planted. The pastel colours are very popular at present and amongst pale pinks, 'Pink Angel', 'Elysian Fields', 'Entorage', 'Pink Confetti', 'Paris Kiss' and 'Mossenova' are my pick, but there are many more with bolder contrasting beards, ruffled standards and contrasting patterned falls. Amongst the pale blues, 'Sapphire Hills', 'Charmed Circle', 'Penchant' and 'Song of Norway' are my favourites.

When we get to the lilacs I must admit that blue and pink often merge in my eyes but, 'Olympiad', 'Creative Stitchery' and 'Lilac Waltz' are stunning to any eyes. If you want perfume in an Iris, 'Scented Nutmeg' is a self lilac-blue that flowers very early and continues to be popular.

So if you have a sunny patch in your garden and maybe you're a little neglectful in the herbaceous border, then give the Tall bearded Iris a try, you'll be amazed.