Why don't you get some ornamental gourd seeds and grow them. They can be planted after frost date is passed and they love compost. You'll get some quick coverage and some cute gourds for Halloween! They have very pretty yellow flowers too.

Moonflowers get big very fast and, in my experience, don't reseed as prolically as their cousins (mornging glories). They have huge, gorgeous, fragrant white flowers that open at night. They are readily available from seed.