Neighbors have a black walnut tree, which leaves me very little space for things like peonies and true lilies. Am grateful that daylilies and iris don't SEEM to mind, but noticed something odd today. I have 2 clumps of Midnight Oil. There is a seven inch difference in scape height between them. The one farthest away from the tree is spot on as far as what scape height is supposed to be. It's the one that's fairly close to the tree that is short. I'm 100% sure they are both Midnight Oil. If juglone affects scape height, that could explain why I've been doubting a lot of my tags. I don't think it's a shade issue, because the walnut tree is limbed up pretty high. There might be a little shade from it very early in the morning, but that's it. It's full sun by 9 am. Please tell me I'm not crazy!

It may not so much be juglone as root competition from the tree. Daylilies will do quite well under deciduous trees but do need a lot of extra water.

I have daylilies planted under a pin oak tree. They seem to do fine and are blooming now. However the scapes are a tad shorter.

sooby said:It may not so much be juglone as root competition from the tree. Daylilies will do quite well under deciduous trees but do need a lot of extra water.

Both clumps have tree competition. The neighbor on the other side has a maple tree.

MOST trees DO take up both available nutrients & moisture at the expense of other nearby species .... Our domesticated crops & ornamentals usually suffer ......

Here in my neck-of-the-woods the negative effects of trees* on nearby plants growth is plainly evident when travelling most rural roadways. That trees 'pirate away' (Dominate in using, in consuming) nutrients & moisture availability at root levels of ALL plants near the tree, is the only common-sense conclusion I've ever been able to arrive at.

*Trees species I'm referring to are spruce, hemlock, Norway Maple, sugar maple, poplar, linden, various ashes and in some cases mixed hedgerows ... Predominantly the ash species & especially maples are planted in the boulevards along roadsides hereabouts.

Simple observation will show that most field crops - dent-corn, soybeans, various grains, even sunflower - grown near these roadside trees are directly & absolutely affected - especially with maples. Radiating out and away from the standing trees are usually very apparent 'bowls' of stunted growth ... dead or non-existing crop plants closest to the trunks of these trees ...graduating to shorter individual plants closest to the tree trunk .... becoming gradually taller - reaching to normal heights - as you move away from the root area of the tree. This is evidence of the 'power' of the root system diminishing as you move out furthr from the tree itself. Such affected 'bowls' usually reach beyond - but NOT by much - the drip-line of the tree canopy.

When travelling along the road with such trees planted 'in-lines' along the boulevard you encounter continuous 'bowls of stunted growth opposite each individual tree with normal crop heights between theses trees and outside of their self-serving root systems. Years ago I needed no other proof of the detrimental effects of 'predatory' trees ... They are the larger, the stronger individuals in their respective areas and they are looking naturally out for their own interests.

Native grasses & 'weeds' & wildflowers & shrubs have evolved to be able to compete & to cope with the nearby dominant trees. Our planted crops such as dent corn - or ornamental daylilies - either suffer OR we compensate with added moisture & nutrients to offset those 'stolen' by the trees.

One more added experience regarding the effects of nearby trees with our own self-interests in controlling every aspect of our gardening expectations ....

Like most natural 'wild' organisms - plant or animal - the individual specimen can & usually will go beyond it's species' norms to take advantage of sources it needs, it wants, it senses, and/or it finds.

Usually a tree's canopy indicates the extent of its root system & defines its drip-line (Look at any wind-felled tree, on it's side, after a storm, with its intimates' revealed above the soil ... However, individual trees have a way of detecting somewhat distant - beyond their normal root zone - sources of needed nutrients and/or moisture. My experiences revealed 3 examples that serious gardeners such as ourselves should keep in mind.

(1) Seeking our reliable moisture. As a young gardener I remember a tree - species now forgotten - that had sent out a feeder root probably twice - or more - its normal distance to take advantage of a long-time dripping barn-side wall water-tap. The farmer discovered just how important this water source was to that tree when he attempted to dig near the tap and discovered a significant 'arterial root' had developed to exploit this predictable water source - sending it back to the tree to use..

(2) I set up a compost box (Plastic commercially available box with lid) and over a few seasons filled it to its max as intended. When I went to remove the compost I discovered the ENTIRE interior of the box was filled with white cedar roots from a nearby cedar hedge. These cedars had found this source of nutrients and exploited it. Their thieving roots were impenetrable within the compost (It was one compact solid 'lump') Then the question came to mind, just what nutrients were still there for my daylilies to use? What I had was a 'block' of fine feeder cedar roots & depleted compost. Raised beds filler at best ....

(3) Manure piles .... I've encountered many examples of trees sending significant feeder roots considerable distances to be able to exploit the nutrients (AND moisture too) of aging, composting manure piles

BOTTOM LINE - Nearby trees, and sometimes NOT so nearby trees, will ALWAYS look out for themselves naturally (Nature - evolution, survival of the fittest et al) ) and will exploit situations to their own advantage .... Thus, perhaps, to your disadvantage.

You may have grubs feeding on the roots of the short one.

When setting up my daylily gardens, I was doing a lot of experimenting to see what they could do. I actually set up a string of daylilies running away from a large Norwegian Maple tree. It went Galileo (Closest), Christie's Big Heart, NoID, small gap, NoID, Christie's Big Heart, and Galileo. After five years of observing this set up, I completely agree with Sooby. The farther you get from the tree, the taller the scapes, the better the branching, the sooner they may bloom, and the more buds you get. I suspect it's a combination of more competition from the tree for water the closer you are to the tree, and also the more sun plants will get as they get farther away from the tree's center.

shive1 said:You may have grubs feeding on the roots of the short one.

Pretty sure it's not grubs on the short one. No sign of moles. Both neighbors and I treated for grubs this year due to extensive lawn damage last year.

Thank you, everyone. I understand what you are saying about tree competition. To clarify, there is one Midnight Oil clump on the north side of my yard (walnut tree neighbor) and one clump on the south side of my yard (maple tree neighbor.) I run into more roots when digging in the bed on the maple tree side. That's why I am suspicious of a juglone connection because it's the north one that is 7 inches shorter. The plants as a whole aren't in any distress in either location. One is just way shorter than the other, and neither clump is newly established.