Don’t Forget the Big Picture

Gardeners think too small, focusing on their favorite perennials and annuals and neglecting the big-impact items, like trees, shrubs, paths and terraces. —Susan Harris, GardenRant and Sustainable-Gardening

Create Flow With Clusters

Planting one of this and one of that rather than massing several of the same plants and repeating clusters of them through the garden for greater impact and a sense of flow. The more you love plants, the easier it is to make this mistake. —Pamela Penick, founder of Digging and Penick Landscape Design

Make Ample Time for Upkeep

Not taking maintenance into consideration. Sure, we all want that gorgeous perennial border that is the talk of the neighborhood, but that border takes a lot of sustained hard work. If you only have two hours on Saturday morning to garden, scale back your plans or your yard will be the talk of the neighborhood for all the wrong reasons. -Patricia Blais, creator and author of Gardensablaze.com and Mysticalblaze.com

Start From Scratch

One of the most common mistakes gardeners make is buying plants that are in full bloom instead of in the bud stage. It’s hard to resist a pretty flower, but once you plant a plant (especially an annual) that is in full color, it is ready to begin its decline phase. Plants that are in bloom contribute “instant color” to the garden but not for long. A good idea is to buy a few plants in bloom and the majority of them in bud stage to extend the color show. —Shirley Bovshow, garden design expert and blogger at ShirleysGarden.com, EdenMakers.com and GardencenterTV.com

Learn to Let Go

The biggest mistake most gardeners make, without even meaning to, is to kill their garden with kindness. Be it they may over-water their plants or over-spray at the slightest sight of an insect. A plant can be wilting from too much water so it is important to really listen to the needs of your plants. —Cynthia Thompson, author of Brambleberries in the Rain

Know Your Size Limits to Avoid Chaos

Not taking into consideration the size of a plant when it matures. When the plants are small, they look sparse planted so far away from each other, so people think by putting them closer together, it will look better! It does — at first! But when these plants “grow up” they will overcrowd and smother each other, and overcrowding encourages the spread of mildew and disease. Another example is planting a tree or bush up too close to the house or foundation, forgetting that a tree has a width span of 20 feet or greater at maturity; when the tree gets too large, they either have to cut down the tree or risk damaging their home. —Jennifer L. Scott, aka "Miss Daisy," executive assistant for Fusion-io and founder of Gardening With Miss Daisy

Don’t Give Up!

I think a lot of beginning gardeners make the mistake of feeling like a failure if they kill a few plants. I think the best gardeners are willing to make a lot of mistakes and learn from them. —Jessica, author of The Garden Blog of a girl growin’ Southern