I suspect this is a tricky one because obviously, any reflection of light is going right back (sunwards) unless a series of refracting mirrors are put in place to literally bounce the light about, directing the light-rays where you want them to focus......and then there are going to be issues with birds and insects flying into glass, fixings which have moveable joints (although this is done with solar panels).

I think it might be more doable to think more about crown-lifting and thinning (I think you call it limbing up in the US) and maybe even creating a separate area of full sun for those light-loving plants which we all want.

Creating outside light with light bulbs and power:
Eventually, LEDs will be lighter, cheaper and more effective, but at present, using artificial light (electric), the costs tend to outweigh the benefits (Unless you are growing cannabis)....so light-collection and energy saving will need to be more efficient and accessible before we can easily alter our external environment without glasshouses, high-tunnels and so forth.

First thing is to correctly identify the limiting factor. It usually isn't light, but water and nutrients. In places it truly is light, like deep under a spruce tree, it doesn't matter because nobody can see in there anyway.

I like your out of the box thinking!

A simpler idea might be replacing the cedar fence with a chain link fence. That would let light through in the early morning and late afternoon.

They do make reflective roofing material. If your house has a peaked roof, a reflective roofing material might reflect some early morning and later afternoon sun into the garden.

Of course, the other option is to try to find woodland bulbs and small evergreens that evolved to grow underneath trees before they leaf out in the spring.

Mindy, I deal with a lot of shade and roots from Maples all along my lot line. One thing we did to start was to use a post and rail fence, which at the time, it was only to allow the borrowed view to extend our lot that wasn't deep. It has actually allowed sun from that side of the lot line late in the day.

But really, I also agree with MadGallica. There are always many plants that will tolerate and even thrive in shade, but shade plus dryness is a killer combination. Our Maples just suck all the nutrients and water from the area that I needed to plant for a screen.

I have tried a lot of different plants that were recommended for dry shade, but many of them still need a lot of extra water to do much at all. And you can't water just the plant, because that creates the issue of the roots of the tree searching out the wet spots and crowding the plants you are trying to grow.

I have to wrap this up right now, but tomorrow I'll explain a little more about what has worked and not worked for us.

Your suggestion of mirrors made me flinch. Of course, I am coming from the perspective of bone dry California. Someone put up sheet metal to keep rodents out of the garden, and three weeks ago it ignited what became a 1500 acre wildfire.

Here is a link that might be useful: Silverado Fire

camp, how can someone with a moniker of campanula have an engineer's mind??? (Obviously, my presumptions get me nowhere!) So, REFRACTING mirrors is what they're called, eh? Brilliant.

The fence is DEF not going to change, but my way of thinking about water can and will change.I am also going to try variegated euonymus growing up the fence.

As a related question, pm2 and others, have you found maidenhair ferns to be as drought tolerant as Japanese painted ferns? And have you ever tried growing lamium up a fence?
mindy

I'm not an engineer, but I am a physicist. Mirrors reflect, prisms refract, or bend, light. I can't imagine any setup which would increase the amount of light from below, not without very expensive mirrors or supplemental lighting which would ruin the effect you're trying to create.

I agree with the other comments - reduce the amount of overhead foliage or fencing blocking the light, or live with shade. When I lived in the Midwest a part of my backyard was heavily wooded with maples. I planted lots of ferns under the trees, and along the east-facing edge which got a few hours of morning light I had shade plants - hostas, rodgersias, ligularias, pulmonaria, sweet woodruff etc. It made an attractive green oasis in the doldrums of summer.

Cheryl

Would you consider painting the fence white? That would brighten things up and reflect whatever light is getting in there....

Dee

Funny Gryfalcon, I had the same thought. Metal mailboxes were causing grass fires around here a couple years ago and the postal workers were having to wear oven gloves to deliver the mail, any piece of glass in a field reflecting sun was enough to spark one off. Seems like it would cause intense heat as well. Then there's always the possibility of hail storms and shards of glass. I'd listen to the physicist, work on the culprit causing the shade rather than trying to bring the sun into the area by artificial means or just go with a shade garden.

What has been happening along our lot line with many Maple tree roots? I have an Arborvitae that is working in more shade than I would have thought was possible. It’s only getting about 2 hrs of sun in the morning and then filtered light later in the day. It’s very close to the trunk of a Silver Maple, maybe 5ft? It is a Western Arborvitae and it was recommended by New England Nurseries, when I asked for suggestions for this site. I have ‘Emerald Green’ in a sunnier location, but the Western Arborvitae does well in more shade with tree roots than the EG in more sun. I make sure it gets water when it’s been dry. I have a soaker hose looped around the base of it, and I use that when we have a dry spell. I do mulch with bark mulch.

I have tried Viburnum maresii, which someone on the shrub forum suggested, despite the fact the shrub is said to prefer a moist location, I liked it so much I gave it a try. And I can say that has not worked out as well as I wanted. It has survived, it has grown slowly and looks great every spring, but when July and August hit, I can’t keep up with watering it and it looks miserable and drops it's leaves early. I’m getting ready to replace it with something else.

I have a ‘Wentworth’ Viburnum next to that which has done really well. It’s very tall, maybe 9ft? Has a lot of berries on it and nice fall color. Doesn’t seem to be bothered by the dryness or the part shade it is in. Gets maybe 3hrs of sun. I don’t give it any special attention. It’s growing right around the drip line of two Maples, one to it’s West and one to it’s North, so it faces East where the 3hrs of sun comes from before it is shaded by another Maple to it’s South.

Three other shrubs that are doing well around that same location, facing East near the drip line of the Maples are an Oakleaf Hydrangea, and two Clethras. I know Clethras are supposed to prefer moisture, but mine have not skipped a beat since I planted them. It looks clean and healthy every year, and blooms very well. I have ‘Hummingbird’ which stays about 4ft tall and spreads out. ‘Sherry Sue’ Clethra is one of my favorites, the flowers are longer and dangle and smell like vanilla up close and it blooms in September instead of the summer like ‘Hummingbird’. Bumble Bees cover it when it is in bloom and appreciate such a great food source so late in the season. Sherry Sue is taller at about 6-7ft. I found that one at Broken Arrow. Of course all of these shrubs are rather casual, but I’ll take whatever grows successfully. They are not in full shade.

On the other side of the yard, in the corner that is the shadiest, I have Taxus, that has done well and does not get extra attention. It is not as dense as it would be in more sun. I have two Blue Hollies that also do very well. These are in the deepest shade, with very little sun except filtered light and a little late afternoon sun. They have grown slowly but are now at the height I need and all these shrubs together are screening that corner of the property.

I have a shrub that I could recommend as growing easily in the shade and is not bothered by the dryness or the Maple tree roots. It always looks healthy and never needs attention. It grew very quickly to about 8ft tall. It also offers white berries for the birds. The one drawback is that it suckers a lot. It’s a Gray Dogwood, a native shrub. It does work in a challenging situation, but you have to be comfortable with the suckering. It is growing, blooming and fruiting with a stockade fence 4ft away on it’s South side, and about 10ft away on the other side of the fence, there is a huge 50 year old Silver Maple, so that is pretty challenging. It does get maybe 2 hours of sun from the east in the morning.

Shrubs I’ve tried and found difficult to establish were, Rhododenron and Azalea, which could be the PH? I have two, they do okay but not growing gangbusters at all. I have a Nova Zembla that is hanging on and growing slowly that is completely under the canopy of a Maple whose canopy is about 6feet off the ground. And it’s about 5ft away from the trunk. I do give that extra water, trying to get it to a decent size to be a screen for me. I have a ‘Purple Gem’ Rhodie that I ignored this year that is in a good amount of sun but in the root zone of a lot of trees and it had yellow leaves on it by mid summer.

I tried two Ninebark ‘Summer Wine’ in about 4 hours of sun but in the root zone of a lot of trees and they did not do well in that location. They are supposed to tolerate dry soil too and they are native. I moved one of them to the corner of the house away from trees but in an equal amount of sun and left the other one there. The one I moved took off and grew into a great shrub, that I really enjoy. The one I left behind did absolutely nothing from one year to the next. Never grew, just barely hung on with sparse growth, no height, and by late summer had dry edges on the leaves even with watering a lot some seasons. I don’t think they would do well in a root zone and shade.

I tried boxwood under the canopy of a Maple and a native Ilex glabra, they wouldn’t grow at all.

For perennials, I have a Maidenhair Fern on the North side of my Garage and that does pretty well. Never looks dry and crispy and it is in one of those areas that doesn’t get a lot of rain. It doesn’t look lush for sure, but it did have a good amount of growth on it this season. I think with supplemental watering it could do well.

Haven’t tried growing lamium up a fence. I have some in very shady areas that doesn’t really spread, but it comes back every year. I have a lot of Japanese Ferns that I like a lot. Hellebores do well, Solomon’s Seal, European Ginger, Hostas. Some woodland phlox and Tiarellas which tend to become unnoticeable along with the Bleeding hearts over the summer, then come back great every spring. Lunaria does very well for me and reseeds. I have some Cimicifuga but I ignore it and by late summer the leaf edges are dry. It’s under a tree canopy with no sun. My most dependable plant in this dry shady area, is Epimedium. I have a lot of that growing all over the garden.

I thought about trying to alter the growing conditions more, as you are doing. Thought about mirrors. About amending the soil more. In the end, I didn’t want to fight it, it takes too much energy. So I’ve just experimented. You always wish you had more options, but considering what I am working with, I’m happy I can grow something that I like. Good luck, I would be happy to hear about any successes you have in these conditions.

pm2, your post is the single best one I have read on CH for gardeners battling shade and tree roots. I wonder if we could do this: how 'bout you cut and paste your above post into a new thread that you title What Plants Can Handle Shade and Tree Roots?

If you could so that, I could be working on my long response about my own experiences fighting the same conditions.

That way, people see Shade and Tree Roots in the title and many more will click on it, and benefit, than from my 'Engineer's Brain' thread.
Yes?
mindy

mmmmm. would surely be of interest to me, having started to garden in a poplar plantation, the entire acreage is rootbound and dry......and yet......unlike pine woods or beech woods which have little undergrowth, my woods are lush and thick with grasses, nettle, many umbels, silene, stachys, As this is utterly new to me, I have spent a lot of time merely observing and have reached a few tentative conclusions,,,,most obviously (to me) is the power and resilience of a stout taproot....rather than surface-y mats of roots. Growing from seed, in situ (much easier to establish), I have been surprised at the vigorous growth in a seemingly hostile environment, as the soil is sandy, shelly and does not appear overloaded with humus-ey material despite 50years of annual leaf-fall,,,,,and I have no means of offering any supplemental irrigation apart from a saucepan on a long stick which I paddle about in the land-drain ditch. I await other people's shadey solutions with much anticipation.

does not appear overloaded with humus-ey material despite 50 years of annual leaf-fall

I am often puzzled by this phenomenon ie an abundance of leaves but not correspondingly rich soil.

Me too.
mindy