1. Visit Construction Sites
Keep an eye out for construction sites with plants that are worth saving mature shrubs, native species, perennials, etc. One call to the construction company, and they could be yours.
Tip: New build sites aren't the only spot to scout for free foliage. Road expansion projects and renos can be just as good.
2. Curb Shop
Once the weather warms up, gardeners get busy dividing and thinning plants. What happens to all those extras? Sometimes they end up at the curb. Hop in your car for a quick lap around the nabe, and you could score enough free bulbs and divisions to keep you digging for days.
3. Grow Plants from Cuttings
Grab a bottle of rooting hormone, and try your hand at growing your own plants from cuttings. It's easier than you may think:
4. Host a Plant or Seed Swap
Have too much of a particular plant or seed? Then, throw a swap party, and trade your way to the plants that you need.
5. Divide Existing Plants
Turn one plant into two or three or more through the simple magic of division. It's good for the plants, and great for your pocketbook.
6. Save Seeds
Collect seeds from your favorite self-pollinating plants, and you'll be able to grow them again next year (without having to buy another packet of seeds).
7. Take Advantage of Volunteers
Need trees for your yard? Then, search your lawn for volunteers. They may not end up where you want them, but they're easy enough to move.
8. Check the Classifieds
Craigslist, Freecycle and even your local newspaper can be a great source for free plants. Look for offers to start appearing in March (or whenever it warms up in your area).
9. Watch for Catalog Promotions
Find a plant and seed catalog that you haven't ordered from before, and you've got a good shot at getting your first order free (usually up to $25 worth of product). Gurneys is just one company that has offered this deal in the past.