I like Garden Heights in Maplewood on Big Bend, just south of Highway 40. They have a nice selection of unusual plants and their stuff tends to be in better shape than what you'll find in hardware store nurseries and the like. The people are friendly and helpful, and their display gardens are lovely.

I guess it depends on what types of plants you are looking to purchase. I have an extensive perennial garden and am always searching for new plant varieties and cultivars to add to my garden. Gilberg's was my go to nursery, however they closed last year. Then I found Sugar Creek Gardens in Kirkwood off Manchester road and I have been very pleased with the selections & variety of plants they offer. Staff is friendly and helpful (and I'll point out that I drive from St. Peters to visit them). I also use many native plants in the garden and buy a majority from Missouri Wildflowers Nursery just south of Jefferson City. They do take orders and bring your plants to the Kirkwood Farmers market for pick up on Saturdays in April, May and September. They do have a web site, but I think I am only able to attach one link per post. So - wwwdotmowildflowersdotnet/ - remove the "dot" and place in "." to see their web site. Several other nurseries I visit over the growing season, but these are the main two where I purchase plants.

Here is a link that might be useful: Sugar Creek Gardens

Those nurseries that are convenient to me (probably that is why I like them): Wiethop (for basics and bedding plants), SherwoodsForest (variety and great quality plants), Summer Wind...formerly Timbercreek (for unusual plant varieties, gift items, statuary etc, and Ahner's (same reasons as Sherwoods and Summerwind). That said, I also buy alot from Lowes, Shop N Save in the spring, and whoever else has the plants I want when I happen to walk in the door. I was once very excited and surprised to find Black and Blue Salvia (guaranitica ?) at Lowes after I had hunted all over St Louis.

God only knows I've spent my time going through the nurseries around here. Here's my run down:

Frisella's - used to love them when they were in North County. The trip to Defiance is good for only once a year now. Tom is great to deal with.

Sherwood Forest - expensive but generally quality material.

Waldbarts - huge selection

Treeland - if you want a decent large tree at a good price this is the place to go.

Summerwind (Timbercreek off of Clarkson) - nice selection of hard to find conifers.

Creekside Nursery (Collinsville) - close, good prices.

Home Depot and Lowes sneak in there from time to time. Home Depot in Hazelwood had 5'-6' hemlocks for $50 each last spring. Pretty hard to touch.

Picked up this thread from last year. So where do you shop for conifers in St Louis ?

Treeland is terrific for good priced and high quality trees and bushes

Thies Farm and Greenhouses- they have a few locations in St. Louis. I have always had good luck with their plants. Everything is grown on site too. University Gardens on Delmar is a smaller retailer and they don't grow their plant material but what they do have is always gorgeous. University Gardens is mainly annuals, and a few perennial varieties. Thies Farm has it all: veggie plants, annuals, perennials, trees, shrubs, water pond plants etc...