How much sun and shelter do the planters get? A clear roof presumably means they don't get rained on but are they in the shade of a wall? Does the wind blow through from Siberia or does the clear roof create its own greenhouse effect?

If you have sunshine and warmth (remember them?) then you might consider a Mediterranean theme - think of silver leaved or fleshy leaved plants. Try a web search for plants for dry soil.

Photos now attached. They are on the drive but don't get much wind blowing through as we are north facing so most wind seems to blow down the street. It doesn't get hot as the roof is quite high but they certainly don't get any rain. The two are against the side wall of the house and the other (its a Clematis not a honeysuckle...oops!!) is at right angles against the shed wall. They also have geraniums in too which are doing ok despite the neglect.

If you want anything much to survive you will have to water it occasionally even in winter. Geraniums kept in a cold place are better dry over the winter as they are less likely to succumb to rot or frost damage. Most things that survive in dry soils also like very good light, and even then there are limits to how dry for things that will grow outdoors in this country. If you know you are going to neglect the troughs you might be better putting in something artificial over winter and some summer bedding in the summer, though its not a very nice solution. I can't think of any climbers that would survive the conditions you describe.

On the other hand, why not become garden friendly yourself - you might be surprised how much pleasure you could get from looking after the troughs and they looked so attractive planted up as in the photos.

You might get away with tough small shrubs, perhaps euonymus fortunii, if you mix water retaining gel granules with the compost before planting?

The clematis may be okay for another year, but the fact is, climbers need a good depth of soil in order to attain proper growth - growing them in troughs doesn't provide that, so it might be better to remove them before they give up on their own, and replace with other things. As others have said, any plant in there will need a drop of water here and there during winter (except Geraniums, which are, as Steragram says, much more likely to survive the winter left fairly dry). In those sheltered conditions, you might be able to grow Geraniums year round in the troughs, even if they look a bit tatty in winter. Alternatively, put summer bedding in for summer and winter bedding (pansies, ivies, small evergreens) in October - might this mean you actually go out and water even in winter, if you've bought winter bedding?

I have watered in winter but not regularly and they are suffering as I lost my husband in September last year and have been less motivated to be out in the cold weather. I am a keen and very successful gardener but these troughs have been neglected. I have looked at drought tolerant plants on the web and will see what I can come up with. I must say fakes are appealing so they look good all year round!!!

Wendy nobody has much energy for anything in the first few months and usually longer. Make life as easy for yourself as you can this year and don't stress - just make it neat enough not to bug you. Your interest and energy will gradually return in time.

How about setting up a drip line from a water butt?

I have a row of various Ferns in pots behind my greenhouse, which get neglected. They are in the shade
and are fine. I would put Ferns in the troughs for some all round greenery. They have shallow roots. Give them a drink now and then in the summer, they are shaded from the hot sun and wont dry out .
Nice to keep the troughs. Memories are of great value in life.