This tree is growing in my yard, it has been there about three years, it is very tall now, about nine feet tall, it had clusters of small white flowers with yellow centres, the blooms in the photos are just about done, and I just took these photos about 3 days ago, I did not plant the tree and am wondering before it gets too big if this is something I should keep? Before the leafs appeared the buds were somewhat furry looking a bit like a Pussy Willow.
It is difficult to be certain due to the blurry portion of the photo. I think your tree is a Black Locust (Robinia pseudoacacia). It will grow to a small tree (30-70 feet in height) with a truck diameter of 1 – 2 1/2 feet, and an open growth habit. Most Black Locusts develop thorns, although there is a thornless variety (var. inermis). The Black Locust is also prone to suckering — which may the the source of the tree in your garden. It has shallow roots which may present nutrient difficulties to other plants. In addition to white, fragrant flowers in the spring, it develops pods in the autumn: the Black Locust is of the family Fabaceae, or the legume pea family. So, whether you should let the tree grow will depend on where it is located in your garden and whether you will have difficulties with its thorns, pods and and propensity to sucker. Despite these attributes, I would note that one of the most memorable gardens I have seen in Toronto, in many years of garden tours, was a grove of mature Black Locust trees, simply under-planted with ferns and lilies.
Here is a link to a site with more information on Black Locust:
If you search images of Black Locust you will find many pictures that will show you mature trees, which may help your decision.
If you would like to submit another clearer photo we would be glad to revisit your question.