About iris: when is time to divide the plants and what are the diseases diseases to watch for and treat?

Planting Instructions

Plant bearded iris in mid summer to early fall, spacing plants 1 to 2 feet apart, depending on variety. Excellent soil drainage is a must. Prepare garden bed by using a garden fork or tiller to loosen soil to a depth of 12 to 15 inches, then mix in a 2- to 4-inch layer of compost. If planting a rhizome (fleshy root), dig a shallow hole 10 inches in diameter and 4 inches deep. Make a ridge of soil down the middle and place the rhizome on the ridge, spreading roots down both sides. Fill the hole with soil, and firm it gently. In clay soil, the top of the rhizome should be exposed. In sandy soil, rhizomes can be buried with a thin layer of soil. If planting container-grown plants, set the plant so the rhizome is at the soil surface. Water thoroughly.



Care

Apply a thin layer of compost around the base of plants each spring, leaving the rhizome (fleshy root) exposed. As flowers fade, cut back the flower stalks to the base of the plant. To encourage a second bloom on reblooming varieties, promptly remove faded flowers and maintain consistent watering throughout the summer. In autumn, trim away dead foliage and prune back healthy leaves to a height of 4 to 5 inches. Once the soil has frozen, apply a layer of mulch to help prevent roots from heaving out of the soil during alternate freezing and thawing. If heaving occurs, don't try to force plants back into the soil. Instead, cover rhizomes and exposed roots with soil. Divide bearded iris every 4 to 5 years, preferably in late summer. Each division should have one or two leaf fans. Older rhizomes that have few white feeding roots should be discarded.



Common Iris Problems



Poor flowering -- is normally due to planting in excessive shade, using excessive nitrogen fertilizer, or planting the rhizomes too deep. Limited flowering may also occur if plants become too crowded and need dividing.



Bacterial soft rot -- is the most serious iris disease. Bacteria enter through injuries or cuts to the rhizome. Soft rot causes the rhizomes to become mushy and have a disagreeable odor. Use of fresh manure or excess nitrogen, coupled with poor drainage, contribute to soft rot development. Dig up and destroy diseased rhizomes. If the rot is not extensive, cut off and destroy diseased plant parts.



Crown rot fungus -- causes a rot at the base of leaves where they join the rhizome and causes them to fall over. It is identified by reddish-brown "mustard seeds" which are produced by the fungus. Trim leaves to admit more sunlight and air movement to the rhizomes; carefully remove and destroy all diseased leaves.



Leaf spots -- After flowering, leaves may become dotted with small, brown spots. Bacterial leaf spot has a watery, streaked appearance. Water-soaked margins around the spot turn yellow. Fungal leaf spots are rust-colored, drier, and more confined. Since disease organisms overwinter on old foliage, cut and destroy leaves of infected plants in the fall. Spray with a registered fungicide during extended periods of high humidity or rainy seasons.



Mosaic -- is a viral disease that causes a mottling of leaves and flowers. It is transmitted by aphids. Remove and destroy infected plants and control aphids.



Iris borer -- The first symptoms of iris borers are small notches on the leaf edge or small accumulation of sawdust frass in early spring. Iris later develop loose, rotted bases and holes in rhizomes. Bacterial soft rot readily attacks borer-infested plants. Carefully remove and destroy old leaves, stems, and plant debris in the fall. A registered insecticide can be applied to the rhizomes in the spring as new growth occurs.



The iris genus includes over 200 different plants. Itis name comes from the Greek word meaning "rainbow", so have fun. Good Luck!

About iris: when is time to divide the plants and what are the diseases diseases to watch for and treat?
Divide iris when they become rootbound %26amp; too crowded to bloom well.
Reply:best time to divide iris is 2-4 wks after all blooming has stopped..during this time sprinke 10-10-10 around them very lightly...they are restoring their energy during this time...waiting this period is an advantage and many ppl/companies will not ship iris you have bought until this time period is up



although my mom moves them all the time



i dont have any problems with diseases but have read that in an iris bed it is best to have a few other types of plants scattered about for disease/insect control...it must work because mine and my moms are all healthy and mutliplying like rabbbits..lol...we just scatter perennials about..she has columbine, wild phlox, bleeding heart and orange butterfly weed in her..i have coneflowers, daylilies and texas bluebonnet and scatter a few annual seeds in mine



mine are just starting to bloom and i just put them all out last year..most are more than double the size i put out and all are loaded with blooms...light lavender opened few days ago..pure white one today and next couple days all kinds of colors will be showing...ppl are starting to slow down and look...hope they dont wreck because of all the rubbernecking/admiring going on...lol
Reply:We usually split them about two weeks after they bloom. Then they'll have a while to get established before they bloom again. Irises are somewhat tolerant; you could dig them up quite often. I've never had problems with them.
Reply:the best time to divide your iris is in the fall

after the flowing time before first frost if you have real small piecves that break off and some space in a cornor plant them there to mature it takes a couple of yeare and you have new ones that are healty you should divide your iris only every two to three years
Reply:Only divide bearded iris every four or five years - after three years in the same spot, they bloom better than newly divided plants. You only need to divide them when the rhizome is getting really large and overgrown - after four or five years ;)
Reply:hmm...well i am always digging them up at all times of year and giving them away...lol..they spread too much!!! I haven't had them die on me yet..
Reply:The best time is after they have bloomed