11 Landscaping Mistakes Homeowners Wish They'd Avoided (and What They Cost)

The most expensive landscaping mistakes come from planting for the size a plant is today instead of the size it will be in ten years, and from ignoring where water goes. Removing a tree that has outgrown its spot costs $435 to $870 for one 30 to 60 feet tall, and fixing a wet yard with a French drain costs up to $7,500 for 100 feet. Almost everything below is cheap to get right at planting time and expensive to fix later.

A thread in r/landscaping asks people what one thing they wish they had known before starting. The answers match what university Extension offices keep publishing: size, soil, water, and a plan.

1. Planting the wrong plant in the wrong place

UF/IFAS Extension puts this first. Match each plant’s light, moisture, and soil needs to the spot. Its example is hydrangeas, which need shade and rich, well-drained soil. Choosing well up front avoids what the agency calls a costly trial-and-error approach. Read the tag, then look at your own yard at 9 a.m., noon, and 4 p.m. before you buy.

2. Skipping soil prep

Soil around a new house often is not soil in the way a plant needs. UF/IFAS notes that construction soil near new homes can contain concrete, paint, adhesives, and grout, and should be amended before planting. A fancy plant in bad soil does worse than a plain plant in good soil. Maryland Extension suggests mixing 1 to 2 inches of compost into the top 4 to 6 inches if organic matter is below 3%. Get a soil test before you spend money on plants.

3. Ignoring mature size

UF/IFAS lists ignoring mature size among its top ten and says to research each plant’s maximum height and width. A UF/IFAS agent also warns that the word “dwarf” in a name is relative, and that people struggle to picture a gallon-pot plant taking over a house side within a few years.

Here is a spacing rule from one planting guide: add the mature widths of two neighbors and divide by two. If one shrub reaches 6 feet wide and its neighbor 4 feet, then (6 + 4) ÷ 2 = 5 feet center to center. The Tree Spacing Calculator does the same for trees and hedges.

Heavy pruning to hold a plant at a smaller size harms its health, UF/IFAS warns. Pick a plant that reaches the size you want on its own.

4. Planting too close to the house

UF/IFAS says to plant shrubs beyond the roof drip line. Close planting limits growth, forces constant pruning, makes house maintenance harder, and reduces airflow, which worsens pests. Two published rules of thumb:

Plant	Distance from the wall
Any shrub	Half its mature width plus 1 ft (a 5 ft wide shrub goes 3.5 ft out)
Small shrub	At least 2 ft
Medium shrub	At least 3 ft
Large shrub	At least 5 ft

For example, a shrub tagged at 6 feet wide goes 6 ÷ 2 + 1 = 4 feet from the wall. The next one over, tagged at 4 feet wide, goes 4 ÷ 2 + 1 = 3 feet out. Another UF/IFAS example is a Southern magnolia planted where its limbs would eventually hang over a driveway. Check the full spread before you pick the spot, not just the height.

5. Putting a tree where it will outgrow the space

A tree needs room overhead and room for roots. One tree-care guide suggests about 10 feet from the house for trees that reach 25 feet or less, 15 to 20 feet for trees that reach 25 to 50 feet, and 30 to 50 feet for taller ones. UF/IFAS cites a tree that would reach 80 feet planted under a 20-foot power line.

Roots are less of a threat than people fear. Toronto Master Gardeners say most foundations are not damaged directly by encroaching roots. The risk is that trees and shrubs pull moisture out of the soil, and that can cause the soil to settle.

What a mistake costs: say you planted a tree 8 feet from the house that now stands 40 feet tall. LawnLove’s 2026 numbers give $435 to $870 for removal at 30 to 60 feet, plus $180 to $525 for the stump. That is $435 + $180 = $615 at the low end and $870 + $525 = $1,395 at the high end, and more if it hangs over the roof or wires.

6. Planting invasives

Check a plant’s status before you buy. UF/IFAS points to its Assessment of Non-Native Plants in Florida’s Natural Areas and gives nandina as an example. Invasiveness varies by region, so what is a problem in one state may behave in another. Your state Extension office or department of natural resources keeps a local list. A few popular nursery plants that conservation groups flag in some regions are burning bush, English ivy, and butterfly bush.

7. Ignoring drainage and grade

Drainage errors are among the most expensive to fix later. UF/IFAS recommends grading the land so water drains away from the house, using swales or in-ground pipes where needed.

The International Residential Code (R401.3), as published by Maricopa County, says the ground must drop at least 6 inches within the first 10 feet from the foundation. That is 6 inches ÷ 120 inches, or 5%. Where lot lines or walls make that impossible, the code allows a 5% slope with water routed to drains or swales. Paved surfaces within 10 feet of the foundation should slope at least 2% away. The Drainage Slope Calculator shows how many inches of drop you need for a given distance.

What a fix costs: LawnLove’s 2026 guide lists exterior French drains at $10 to $75 per linear foot, so 100 feet runs $1,000 to $7,500. Interior drains run $40 to $100 per foot. Restoring the lawn afterward adds sod at $0.90 to $1.80 per square foot. A trench 100 feet long and 2 feet wide is 200 square feet, so sod costs 200 × $0.90 = $180 to 200 × $1.80 = $360. Run your own numbers with the French Drain Cost Calculator.

8. Volcano mulching

Piling mulch against a trunk is common and harmful. University of Vermont Extension says mulch should be no more than 2 to 4 inches deep and kept at least 3 inches from the root flare, spread in a wide, even ring out to the drip zone. Mulch against the bark holds moisture and promotes decay. Burying the flare cuts oxygen to the roots, and deep mulch can trigger roots that grow around the trunk. The mound also gives voles cover to chew the bark.

For a 100 square foot bed at 3 inches deep: 3 inches is 0.25 feet, so 100 × 0.25 = 25 cubic feet, and 25 ÷ 27 = 0.93 cubic yards. The Mulch Calculator handles any bed size.

9. Using the wrong groundcover

UF/IFAS says turfgrass fits poorly in shady spots, steep slopes, and small areas that are hard to maintain, and that other groundcovers need fewer resources there. It also cautions against replacing groundcover with rock or artificial turf, which does not support wildlife, adds to yard heat, and may break HOA rules.

10. Designing without maintenance in mind

Curved paths, narrow turf strips, widely spaced trees, and mixed mulches make mowing and upkeep harder, according to UF/IFAS. A design you cannot maintain quickly stops being a design. Before you finalize a bed shape, picture yourself mowing next to it.

11. Planting without a plan

UF/IFAS recommends picking a consistent theme, such as a general shape or form, so the landscape looks unified, and choosing drought-tolerant, low-input plants to cut watering, fertilizing, and pest control. A plan on paper, with plant names, mature sizes, and locations, costs nothing and catches most of the mistakes above.

How to decide before you plant

1. Look up each plant’s mature height and width and write them on a sketch of your yard.
2. Space plants with the width rule and keep shrubs beyond the drip line.
3. Walk the yard after a heavy rain and note where water pools or runs toward the house.
4. Get a soil test and amend before planting.
5. Check an invasive-plant list for your state.
6. Mulch 2 to 4 inches deep, pulled back from every trunk.
7. Phase the work. Put in the grade, drainage, and trees first, then shrubs, then beds.

Sources

• UF/IFAS Gardening Solutions: Top 10 Landscaping Mistakes
• University of Vermont Extension: Beware the mulch volcano
• Maricopa County: Building Elevation Plan Requirements (IRC R401.3 grading)
• LawnLove: How Much Does Tree Removal Cost in 2026?
• LawnLove: How Much Does a French Drain Cost in 2026?
• University of Maryland Extension: Starting a New Lawn
• Lawn & Landscape: Five common planting mistakes
• Treenewal: How far should trees be from the side of your house?
• Toronto Master Gardeners: Trees near house foundations
• Lancaster County Conservancy: Nature’s Least Wanted (invasive plants)