Laburnum's seeds are very poisonous but I have had them around the dogs for years and no harm has come. It can also become very tall and willowy. This is a great problem and a great asset at the same time. Young trees can grow so fast that they are not really stable or grabbing the ground. I reccomend keepng it pruned back till it has been in the ground for a couple of years, unless you give it significant support. The asset, is the possibility of growing it on the side of a house or on a trellis, like a vine. You could easily grow five of them...If you can afford such an extravagance... in a circle and weave the branches together to give mutual support to them and also to provide a sort of roof, over a living summer house or gazebo. Laburnum tunnels are quite common in Europe, there, a metal or sturdy wooden tunnel is constructed with a walkway underneath, perhaps following a border or property line etc....The trees are planted along the route and trained very easily over the structure. The racemes of yellow hang down through the roof and the leaves give plenty of shade for a nice stroll. If you are good a propogating cuttings, this may not be so far fetched an idea. The same is possible with Wisteria.
It likes a little sun and good soil, but it even thrived in the rocky talcum powder, I have it in here, in Mansfield Ma.