Posted February 9th, 2017, 07:12 PM
June 1st means the gardens officially close at 6pm - so realistically the only way you'll see them at all is with a ships tour. 3h30m is not enough IMO to do justice to the gardens - by the time you get there and back, that leaves approx 2 hours on-site. That's enough to rush around the whole place but not to hang around anywhere. On the plus side, you will have daylight until a little after 9pm on June 1st, so at least you'll be able to actually see the flowers under natural light.
If Butchart is a 'bucket list' place for you I'd consider the ships tour - returning after the cruise from Seattle or even Vancouver is an even less efficient trip. To really
do them justice, if this the last port stop before returning to Seattle, you could consider a hotel overnight and a longer visit next day followed by taking a ferry back to Seattle or Vancouver (or even flying home from YYJ).
Other things to see - since you're in official Canadian Summer (after May two-four, before Labour Day) there will be more shops with extended opening hours, especially on a cruise day, but most tourist attractions still button up about 5pm (Victoria is not exactly a party town).
Parliament won't be open for tours (last starts at 5pm), but once it gets dark will look pretty durn good all lit up, as does the Empress and various other downtown buildings around the harbour. The Empress usually starts extending their 'afternoon' tea hours into the evening by the end of May - far from cheap at $75+pp but very popular. Royal BC Museum unfortunately only has extended evening hours Fri/Sat, but the Imax cinema will be open in case that's of interest.
Evening whale-watching cruise
would be my pick - you have more than enough time to book an independent tour rather than an overpriced underlength ship version. Sunset on a small boat is pretty cool, and there's a very high chance of seeing Orcas out of Victoria.
Princess: Emerald, Golden x3, Island, Star x2
NCL: Gem, Pearl
Edumacational kiddie cruises: SS Uganda