I love this place. It's really a hidden jewel in a slightly shabby side of uptown. It's easy to miss (small parking lot), but well worth the time. Quiet, peaceful, a huge variety of roses (and some other blooms, but definitely the emphasis is roses), some seating for a picnic lunch. It is not a big business type of place (their gift shop is small, there usually only is a handful of employees working, and it's only open three days a week for limited hours), but it's gorgeous little oasis in the city. It'd also probably be lovely for a smaller wedding or event. They are a wedding venue, and I have heard they are reasonably priced.
Admission is free, but I usually leave a donation since I appreciate being given the opportunity to enjoy the grounds.