The laburnum tree is a garden death trap and could possibly give off in its roots natural herbicides called allelochemicals. These chemicals are used by some plants to inhibit the growth of any other plant around it to increase its chances for survival of itself, its seeds and seedlings. The prime example of this is the black walnut tree. These allelochemicals can remain in the soil long after the plant is removed thus making it difficult to grow anything in the affected soil for years. This condition is known as Soil Sickness. Even in the seemingly peaceful garden there can be quite a battle going on between the plants themselves. Again, I don't know wether your laburnum is capable of this, though your observations indicate a good probability of such. There are plants that do have a resistance to this chemical, I do not know if the one you mentioned has this capability. A very interesting topic, isn't it? Thank You For The Question.

Such melodrama in the first sentence, Eclectic, less is more.

Laburnums are beautiful trees, as with all plants, Mollysheba, you need to plant accordingly because they all have specific requirements and needs :-)

If you want to call me an "imbecile" Eclectic please do it in public and not in a PM.

What an odious little man you are.

It's difficult to grow other plants under many species of tree as the tree roots take most of the moisture and nutrients making it hard for other plants to compete. Certainly cherries, sycamores, leylandii and so on are notorious for having "dead zones" around their bases. And hedging plants often do the same. You may have to use trial and error to find plants that will survive in this area Mollysheba.

Spring bulbs may work as they should be coming to an end when the laburnum's leaves start to make a lot of shade.

Montbretia are well known (I almost wrote "notorious") for growing almost ANYWHERE and will outcompete most plants.

Have you tried some of the tougher perennial geraniums (varieties of G.endressii come to mind). You could try scrounging cuttings and divisions of "good do-ers" from friends and relations. You're looking for the bombproof reliable toughies that people are able to give away for you to experiment with.

Eclectic I think you are going over the top... Whilst we don't have a laburnum in our garden they are pretty common garden trees in the UK. Molly have you tried the real toughies like vinca and ivy? They seem to survive just about anything! You could also try hardy cyclamen and chionodoxa which are almost a weed in our garden. If your soil is neutral or acidic some of the heathers might do okay.

Sorry to hear of your misfortunes with the Laburnum border. I'm wonderinhg if a weed killer has been applied in the vicinity of the tree. Some chemicals like sodium chlorate do migrate in to nearby areas. Have you tried for more than one year. I have laburnum trees in the garden in excess of 50 years old and they are in an acid environment but I have no problems as you will see if you look at my last but one blog, "2011 just goes on (1)" The laburnum seeds self sow like mad so I throw away at least 100 seedlings every time I weed this border. I have hydrangeas, pittosporum, weigela, rhododendrons, cotoneaster and heathers living very happily with the laburnum. I also have primroses and spring bulbs, snowdrops, English bluebells and crocus. I hope this is some help.
Another problem could be if the area is too well drained making it difficult for other plants to thrive. Most plants need to be coddled by giving them water for the first year to help the roots get enough water to sustain the plant. Have you been in one of the arid zones in the Uk this year or have you like me been in a very wet zone. Here in Scotland we have not needed a hose at all it has rained so much. Is it shrubs or herbaceous plantsa you are trying to grow. Sorry for all the questions but the answers will help members help you to get to the root of your problem.

I have a 14 year old Laburnum in my garden and its growing among several shrubs its an absolute joy and its does nothing to harm my garden. I think lack of water or poor planting technique is much more likely to have killed your shrubs.

I think you will find that it is only the seeds of the laburnum that are poisonous and the improved variety Laburnum x watereri 'Vossii' hardly sets any seed. The only tree that I know of that inhibits any growth of competition plants is Juglans nigra, the black walnut which produces juglone. As suggested it is probably the lack of moisture which is your problem. Heavy mulching around the roots will give an improved planting medium for new plants.

Louise1, after reading your comments concerning the insult you have had, I find that the person in question has had his account deleted. This is the first time I have seen this happen since joining this site for 'Gardening Friends', and I feel ashamed that people can be so rude. Gardening is not an exact science and it is the differing views of members which makes it so interesting and enlightening.

Welcome to GOY Mollysheba. Just for your information Monbretia has been renamed Crocosmia. You may find a plant similar to yours on here but under a different name. Every now and again names change as the scientists make new discoveries about the plants DNA for example.
http://www.thepoisongarden.co.uk/atoz/laburnum_anagyroides.htm is a website which gives details of poisonous plants. It does away with the widely held belief that laburnum is fatally dangerous to children.

Jimmy, sadly every now and then the Boys have to delete an A/C when someone goes 'over the top' in their behaviour. I am sorry that Eclectic went so far past good manners that he has been deleted.

Scotsgran I may be wrong by I 'think' Crocosmaia is the 'tame' version of Montbretia...

got me investigating MG and this is some of what I found
The Common Montbretia, (Crocosmia x crocosmiiflora) was the first hybrid Crocosmia and was bred in France in 1879 by Victor Lemoine of Nancy.
The plant Montbretia was named after Antoine Fran's Ernest Conquebert de Monbret, a botanist who accompanied Napoleon on his Egypt campaign in 1798.
Crocosmia, (kro-KOS-mee-ah), is so named because the dried leaves smell of saffron when rubbed, and after the Greek words, krokos for saffron and osme for smell .
The Common Montbretia (Crocosmia x crocosmiiflora) was bred by crossing Crocosmia pottsii (a species that grows near streams) with Crocosmia aurea (a woodland species).
This is why most Montbretia prefer a little shade, lots of water, organic matter and nutrients.
Most hybrids bred before the second world war were Montbretia Hybrids (Crocosmia x crocosmiiflora)
Montbretia bear much larger flowers if grown in pots with plenty of organic matter and feed, and they make superb specimen plants for containers on the patio.
Some Crocosmia are pollinated by South African sunbirds in the wild.
On the west coast of the USA they have become an invaluable plant for attracting hummingbirds
into peoples gardens, they provide hummingbirds with a rich source of nectar.
In the UK the bright colours of Crocosmia also attract hoverflies to the garden. Hoverflies are a natural predator, and like the ladybird, eat aphids and greenfly.
Crocosmia leaves should be left on after flowering and not cut back to the ground as the old leaves will protect new emerging shoots from frost and hedgehogs will also hibernate in the old leaves which they roll around themselves to form a ball.
If I have whetted your appetite for more about this much maligned plant then do visit http://www.thecrocosmiagardens.net/5330364
It is the website of Mark from Caister in Lincolnshire who is the holder of the NCCPG National Collection Holder of Crocosmia. It is a fascinating website and I wish I lived closer as a visit to his garden on an Open Day would be a thrilling experience. The Collection open days in 2012 will be on the 19th and 26th August. There are 270+ varieties in the garden.

Wow - you learn something new every day Scotsgran!

Thank you for setting me thinking Mg. Lucky Lincolnshire Goyers who can visit this amazing place. Sorry for side stepping your question Mollysheba but if you live near this garden you could have a lovely border of full of Crocosmias.

Well I am not sorry! I am Glad to hear he has gone Louise, having had unpleasant PM's when I first joined I know just how horrid it is.

Hi Scotsgran it is interesting you mention acidic conditions for Laburnums. I was told when mine did not flower very well in about its 6th year to mulch with about 40-50Litres of ericaceous compost every spring. It transformed this tree and has flowered profusely every year since and the leaf colour is much improved. Sadly they are short lived trees about 25-30 year usually, so well done with yours.

Ah I think you misunderstood me Drc I am sorry that he was so rude not that he was deleted...

It would be helpful to know what has failed. As you say Drc there is usually a way round most problems. It is just necessary to pinpoint what may be the cause of the problem. I planted 3 Clematis montana before finding it thrives in the worst situation possible where it is battered by the prevailing wind and rain. I later found out that clematis like quite wet feet not the feet in shade and the top in sunlight as I had been advised. I have benefitted enourmously from the wide fund of knowledge available from members.

I did misunderstand MG glad I was wrong.
I agree that Clematis do like a lot of water Scotsgran, I have several and all of them seem to like different conditions but all seem to like being planted very deep.

No prob. Drc... I think this has made us all a little bit prickly -)

:))

What a fascinating debate! We have a laburnum tree in our garden which is at least 25 years old (possibly as old as 40 years). It's growing on a chalk slope and hasn't had any special care in the last 25 years. - And our soil can kill acid loving plants in days! It is a magnificent tree, and attracts so many wasps each year that it actually buzzes with a most extraordinary deep hum when you stand under it. It doesn't poison the soil. In fact the grass under it is the best in the lawn.

Thank you for that info Jaquihogan and welcome to our world of GOY. As Mg says we learn something new all the time, from each other.