Weeds

I have mulched all of my garden with crushed leaves and pine straw on top of that and have hardly any winter weeds EXCEPT for my iris bed. I didn't mulch there so that I wouldn't lost my babies to rot. Now they're covered in weeds. Is there anything to do besides just had weed them?

It depends on what type of iris you're talking about. Most beardless irises can and should be mulched to help retain soil moisture. Bearded irises are prone to rot if grown in soil that is consistently moist, so mulch is trickier around them. Bearded iris beds can be mulched as long as the mulch is not allowed to cover the rhizomes. Keep mulch pushed several inches away from the rzs and make sure the soil surrounding the rzs has adequate air flow to allow it to dry out. If your soil is heavy or poorly drained, you might be better off avoiding mulch around your beardeds at all.

Hand weeding is a pleasant enough way to spend a few hours every now and then, but you can also help prevent new weeds from sprouting by applying Preen (NOT Preen and Green) to your beds a couple times a year.

Laurie

The irises I was talking about are the bearded ones. I should have been more specific, especially since I have the yellow flags and Louisianas.

Preen is an excellent idea. I didn't even think of it. Thanks so much.

MANTIS

I rarely pull weeds. My mulch is heavy between plants and right up to the roots of everything but the Bearded Iris. I'm lazy. It helps me avoid dragging a hose around too since mulch holds in the moisture.

Wandasflowers, What type of mulch do you put down and when in the spring?

I love iris but have not mulched because of rot. We have such heavy clay soil. I am wondering about also adding sand. I have added compost and dad's oldest manure. What do you think? Should they be on a rise or is your iris planted flat. Where do you get Preen? Lowes? Teresa

Teresa,

I also have extremely heavy clay soil, so I know your pain. ;-) I have amended it over the years with aged horse manure (mixed with decomposed pine sawdust), gypsum, alfalfa meal, perlite, peat, and sand. Sand has proven to be the most effective amendment to date. Manure/compost/leaf mold (anything organic) will quickly decompose and dissipate in clay, leaving you back where you started with compacted concrete clay around your iris rhizomes. Gypsum supposedly chemically alters clay particles and binds them into larger pieces that compact less easily, though I haven't really noticed any difference after amending heavily with it for several years. I imagine the perlite is helping somewhat, but it's quite expensive.

All of the above serve valuable functions in feeding and/or altering the consistency of clay soil. The trick is to keep amending with everything you can get your hands on. Do it every single year. In the years when you are not digging and dividing your irises, you can still amend the soil between iris rows and top-dress around the irises with gypsum.

Raised beds or rows are extremely helpful for bearded irises in clay soil. They improve drainage substantially and provide more depth of friable soil into which the plants can sink their roots. Drainage is not much of a problem in my clay, but soil compaction is. Compacted clay around iris rhizomes can suffocate them and leave them vulnerable to rot infections. Even if they don't succumb to rot, they can't seem to expand into decent sized clumps when surrounded by concrete clay.

You should be able to pick up Preen in any garden center or garden department in the "marts".

Laurie

I've been seriously thinking about getting tons of sand to amend my soil with. I have a somewhat unique situation. Before the houses were built in back of my house there was a seasonal stream that ran widthwise through my back yard. When the houses were built they added a retention (detention?) pond, thus "diverting" the stream. The only problem is that the area still acts like a stream when it rains. The soil there holds lots of water and compacts very heavily. Thus the need for sand. But what kind? Builders sand? Coarse river sand? I don't have a clue. Any advice? Thanks ahead of time.

Pins2006,

I suggest you amend with the coarsest sand you can aquire. The finer the sand particles, the more likely they'll bind with the clay to produce an even more concrete consistency than you're dealing with now. But from your description, it sounds like your best strategy would be to choose irises that appreciate and thrive in damp-wet growing conditions. Louisiana irises might be ideal for your yard, esp. planted in and around the stream bed itself.

All the best,

Laurie

Thanks, Laurie. Actually, I've done just that. I ordered some for this spring and I have a couple of white ones (no name). I really do like them. Plus, I'm up to my eyeballs in the yellow Japanese flag irises (hint, hint).

I have as heavy a clay soil as anyone. (It was a construction material http://www.rootsweb.com/~casfvgs/mission.html ) I don't amend it at all for the bearded irises and I have more irises than I can shake a stick at. I try to keep the top of the iris rhizomes exposed (at the surface of the soil) and I do not mulch in the immediate vicinity of the irises, though some of them have grass growing right up to them. Twice a year I pull out the dead leaves and debris and junk that accumulates around the plants.

I've heard that bearded irises should not be given food high in nitrogen.

I used PREEN several years ago.It killed the weeds, but my irises did not seem to do well at all after applying. At that time its use on irises was not listed on the container, but I was desperate to get rid of the weeds. Unfortunately, it or a combo of other factors also got rid of most of my TBs.