We did subcontractor work for a contractor in Oregon - is there any paperwork needed on either side?

We are a licensed Lawncare company in Walla Walla Washington. We recently did work for a contractor who has a house here. He is also licensed and bonded in Oregon as a contractor. Are there any forms which need to be filled out and/or filed?

You will need
Form W-9
If you’ve made the determination that the person you’re paying is an independent contractor, the first step is to have the contractor complete Form W-9 (PDF), Request for Taxpayer Identification Number and Certification. This form can be used to request the correct name and Taxpayer Identification Number, or TIN, of the worker. A TIN may be either a Social Security Number (SSN), or an Employer Identification Number (EIN). The W-9 (PDF) should be kept in your files for four years for future reference in case of any questions from the worker or the IRS.
Form 1099-MISC
Form 1099-MISC (PDF) is most commonly used by payers to report payments made in the course of a trade or business to others for services.
If you paid someone who is not your employee, such as a subcontractor, attorney or accountant $600 or more for services provided during the year, a Form 1099-MISC (PDF) needs to be completed, and a copy of 1099-MISC (PDF) must be provided to the independent contractor by January 31 of the year following payment. Starting with 2016, you must also send a copy of this form to the IRS by January 31.
Also note that independent contractors may have their own employees or may hire other independent contractors (subcontractors). In either case, they should be aware of their tax responsibilities, including filing and reporting requirements, for these workers.
There are certain situations where a 1099 is not required. These exceptions are listed in the 1099 Instructions (PDF).

Yes. A written contract describing what work you’re doing for them, how much you’re getting paid, time lines, etc. You need a subcontract agreement just like you need an agreement with a homeowner, no different. Nothing beats a WRITTEN contract between 2 parties for both of your protection in case one decides not to perform. GOOD LUCK!

You need to send people you worked for your w9 form for taxes.
Sometimes they will ask for an additionally insured form from your insurance agent to them. It’s free; just ask your agent to send it to them.