I garden in extremely heavy clay and add lots of well aged horse manure to my beds when I redo a bed. However, I dig from the oldest sections of my manure pile - sections that have been composting for at least 10 yrs.

If your neighbors have an old pile that you can dig from, then go for it. Just make sure you work it as deeply and thoroughly into your soil as possible before planting. If, however, your neighbor's manure pile is less than a decade old, I wouldn't use it in a bearded iris bed. You could certainly get some for your own compost pile, though, and accelerate its composting by turning and watering it regularly, and making sure it is mixed with an appropriate percentage of "browns".

Laurie

I have sandy soil and also use horse manure.
I don't get to age mine nearly as long as Laurie (I'm jealous!). I've found that if I turn the manure a couple times a year, by the beginning of the 3rd year, it's ready to use. I also use rabbit manure (which can be used without much composting as it's not as hot as raw horse manure).
However, all this said... I have an iris bed next to our miniature horse pen. The horses find the corner next to the iris's to be the best for their droppings. These iris are semi neglected most of the year and I only remove the droppings that pile around the iris's twice a year, so most of the year these iris are surrounded by raw horse manure. They thrive there!
In conclusion, I agree with Laurie.. Get the oldest stuff you can to be safe.
Happy tilling!
Heidi

I have a small lot and three horses, so I've been using pure horse manure for all my raised beds, I let it compost for about six months to A year then I'm good to go. horse manure is diffrent then other manure, for one horses have a poor digestive system, this means that grass seeds and such pass throw and can grow. on the other hand if your letting it set for ten years this would not be a problem, but horse manure breacks down really fast as it passes throw the horse faster then most other animals.

Horses have no known harmful bacteria in their poo, unlike say cow, (one reason horses are allowed on hiking trials as thier poo is not harmful to humans and has low inpact on water supplys)

This being so I find it best to use horse compost at around a year, I cover mine with a trap so not all is lost in run off.

My Iris, hostas, ferns and everything else have done super! I belive it is due to the horses. and like I said I plant in full horse compost that is around a year old. I control grass by putting on a bark mulch and then I weed the beds and After that first weeding I don't have trouble with grass, unless I add new compost.

You should see my dads veggie garden, it's almost pure horse compost too, and it does so well!

I planted a bunch of old wal-mart iris a little late last year and they all bloomed their first year! I buy sick plants off sale racks and by next year they look wornderful!

Like Koidom, I let mine age from six months to a year. My rule is if the manure is black, peaty and doesn't smell anymore, it's good to use.

Okay. I pulled up this old thread because it is time to plant the new rhizomes that just got here. I have some very aged horse "helper" that I got from a local horse farm. There is no odor as such and my other plants have been thriving on it since I started using it in earlier Spring of this year. Tell me how best to use it with iris, please. Do I put it below existing roots of these new rhizomes as a layer for them to grow into or do I till in as evenly as possible as I plant them, or what? All the detailed info you can share, please.Or do I wait to fertilize later in the Fall? If so, how would I apply it to the new and already established iris?

I live in North Idaho and use my horse'e manure on my iris beds after it has aged 6 months to a year. For new plantings I till about half parts manure in with my soil (it is quite sandy)before planting iris. For established beds, I'm lazy and just dump manure on top- the iris still do fine.

If spread thin horse manure doesn't need to age at all -- it won't burn. The only thing that will burn from a horse's stall is shavings soaked with urine -- that's very very high in nitrogen! If you're worried about seeds you can try to get manure where it's piled up deep -- the stuff gets so hot in the center of the pile that the weed seeds are killed. I get weeds no matter what so it's all the same difference to me.

Thank you so much for all the good experienced advice. I feel alot more confident now. I wanted so much for the iris to benefit from our wind fall. The horse farm said we could have all we wanted, any time we wanted some.
I'll start using it immediately on the iris. It would be so nice to see them thriving like all the other plants we have used it with this year. You gardeners are great to share your practical knowledge. One of the fun things of working with the earth and gardening is the kind of people it draws. Your advice is "priceless"!