Question
What are the benefits and non benefits,if any, of having hawthorn in you garden?
How dose it help in the contribution of the ecosystem?

Answer
The bright green, shiny spring foliage is quite attractive, as are the spicily fragrant flowers that resemble apple blossoms.  The fruit provides food for birds and possibly other wildlife.  The thorny, dense branch structure provides secure nesting sites for some birds.

In my area this shrub has become a noxious weed.  It is also unpleasant to work around because of the thorns.  Farmers hate to find it in their pastures because the thorns can cause costly punctures in tractor tires.  It may be a vector in the spread of some diseases.  Frequently I see it defoliated by late summer, making it quite unattractive.