casual outdoor wedding

The formality of your invitations will let guests know how formal you're wedding is. Make sure they fit the feel of your wedding! Also, you can put on your wedding website that it is dressy casual. I think many female guests will Google the location of your venue to check it out and they will get a feel for the formality that way too

You would just set the tone with your invitations and website. Spread it by word of mouth

PP's rock.

I did get an invite last summer that said, in the corner, "dress? Sassy and comfy!"

I put on my wedding website.

"Dress casually and comfortably!"

& I called it a backyard bash! xD

Also our invitations were colorful/cartoon and fun!

@Celia said I rock! (eye heart emoji) my day is made

I put on my wedding website a detailed description of the venue, both ceremony and reception and left it up to the guests to wear what they want but recommended comfortable shoes and sweater in case in gets chilly.

I too am having a small outdoor ceremony on the grass followed by a dinner so I plan on mentioning these details on the website.

If you don't want a website you could put the word out for women to wear comfy shoes.

I feel that just the dress code comment does not cover the shoe situation.

I would describe the venue on your wedding website so the ladies can decide on the shoes.