I have a washington hawthorn tree?

Hawthornes do not require male female.

To start at the beginning, are you sure it is a washington hawthorne? It is more common than you would think that a nursery might sell a mis-labeled plant. I know you said it has thorns, so probably it is, but always good to check the most basic things first.

Do you fertilize? What is your soil like? Where do you live?

Flowering and fruiting is the plant's way of ensuring it's genetic material survives into the future. You will often find that a tree that is about to die will bloom prolifically. On the flip side, it has also happened that a tree that is 'very happy' does not flower. Sometimes they need to be in just a little bit of stress to flower. I have seen this happen.

So, get a soil test from your local agriculture extension office and start with that. There may be a nutrient shortfall somewhere. IF not, ask their advice.

Here is how to find you local extension office http://www.csrees.usda.gov/Extension/

Good luck

Are you in the climate most favorable, the zones 5-9? If so, you may have a disease or pest problem! http://hort.ifas.ufl.edu/trees/CRAPHAA.pdf

http://plantfacts.osu.edu/pdf/0246-345.pdf

http://landscaping.about.com/gi/dynamic/offsite.ht...

It could be a male/female situation.