Wingecarribee Council's gardening team has been brainstorming, designing, digging and planting since the end of last year to bring the superheroes to life for the children's themed Tulip Time Festival.

With just seven sleeps to go, park supervisor Alexia Hill and her team of 10 are into the final touch up stages.

"The tulips have started to come out a little early, but we can't help the weather," Ms Hill said.

"It's all coming together really well.

"We've used more annuals than usual, which has helped to give more levels in the garden and really highlight our tulip designs."

When Ms Hill and her team were informed of the children and rainbows theme there were plenty of brainstorming sessions to work out the best designs.

And the final decision was two feature garden beds: Batman and Superman.

"We used line marker paint to draw out the designs and then it was just a matter of filling in each section with the appropriate tulips," Ms Hill said.

"It's fiddley. You really have to make sure you don't mix up the colours.

"We're going to have black tulips for the bat symbol, which should look very cool."

The inmates at Berrima Correctional Centre helped out with the initial bulb planting.

And over the last few months the gardeners have been in every week doing maintenance, laying turf, and completing the final plantings before the official opening next Thursday.

"Most of the group have been with us for a couple for years now," Ms Hill said.

"We've got a great team and they've done a fantastic job."