Why do iris plant bulbs grow better in tree shave?

The bulbous Irises, which includes Dutch Iris %26amp; some Reticulated Irises can grow in full sun to light shade.

http://www.tesselaar.net.au/growingguide...



They bloom early in the season when the area under the trees are actually sunny at that time...because the trees don't have their leaves yet. This is similar to planting sun-loving tulips under trees.



The Bearded Iris needs full sun but aren't planted under trees. They bloom later in the season %26amp; wouldn't do well growing under trees because it's too shady for them. They have rhizomes that would rot in an area that's too shady. They like the sun beating down on them through out the summer.



Iris Lazica is different from other rhizomatous Iris %26amp; "enjoys light shade and moist soil. The best place to grow it is in a sheltered spot in dappled shade."

http://www.webgardenguide.com/Iris_lazic...



Different types of Iris require different growing conditions, so it would depend on the type of Iris you're planting %26amp; your climate to determine if it would or would not do better growing under a tree.



Good luck! Hope this helps.

Why do iris plant bulbs grow better in tree shave?
WHERE TO PLANT

Irises require at least a half-day of sun. Some shade is beneficial in extremely hot climates,(but ONLY hot climates) but in general irises do best in full sun. Provide your irises with good drainage by planting on a slope or in raised beds.
Reply:Assuming you meant "shade", I have to say they don't. All the varieties of Bearded Iris I have grown do better the more sun they have, and they thrive in full sun as long as they get plenty of water.



Are you dividing the rhizomes every 3-4 years? They need that to thrive.