Five Mistakes to Avoid in Your Garden

Have you ever planted something with absolute confidence only to watch it struggle? You're not alone! One of the things I love most about gardening is the trial and error and ability to learn and grow (and yes, the pun was intentional).

Through personal experiments (some successful, many not), professional training, and years working alongside clients across Evanston, Chicago, and the Northshore, I've compiled the top five gardening mistakes I've either made personally or witnessed so you can save yourself the time, money, and heartache that comes with learning these lessons the hard way!

1) Wrong Plants, Wrong Location

It’s easy to fall in love with a plant or shrub only to find it won’t thrive where you’ve planted it. I learned this lesson the hard way when I planted three beautiful hydrangeas in a shaded corner of the backyard. Without enough sun, these hydrangeas produced limited blooms and just didn’t live up to their full potential.

Once I recognized my mistake, I offered these hydrangeas to a friend with a perfect, sunny spot, and sure enough, they transformed into the gorgeous flowering plants they were meant to be. When choosing plants, be realistic about the condition of your site's conditions:

Sunlight reality check: Many plants require full sun to produce flowers, while others will burn. Track sun patterns throughout the day and seasons—that "full sun" spot might only get 3 hours in summer, especially once trees leaf out.

Moisture matters: Some plants love swampy conditions, and others thrive in dry soil. Note which areas stay wet after rain or dry out quickly.

Mind your soil: Sandy, clay, or loamy soil dramatically affects which plants will thrive.

Location, location, location:  Read the labels at the nursery or do a little internet research to confirm a plant’s preferred environment. Consider wind exposure and temperature fluctuations, especially if you live near Lake Michigan.

The more you’re able to plant the right plant in the right spot, the more success you’ll have.

2) Overplanting: Patience is Key

Thanks to social media, we all crave that picture-perfect garden right now. The problem is that nature operates on its own timeline. I know it’s tempting to buy and plant lots of plants to fill your outdoor space. But trust me, those plants will get bigger, more crowded, and far less manageable. You need to trust nature's timeline and keep the following in mind:

First impression: A newly planted garden with proper spacing might look "unfinished" for 1 - 2 seasons. I always tell my clients that even if their garden looks a bit “airy” to start, plants will fill in over time!

False fullness: Plants placed too closely together might initially look full but will quickly become overcrowded. I always design with each plant's mature dimensions in mind—that tiny one-gallon perennial might spread three feet wide in just a few seasons!

Overcrowding consequences: Overcrowding leads to poor air circulation, increased disease pressure, and competition for water and nutrients.

Correction challenges: Keep in mind that it's so much easier to add than subtract established plants later.

I always tell my clients that even if their garden looks a bit “airy” to start, plants will fill in over time. You can always use annual flowers as temporary fillers while waiting for plants to reach their mature size or embrace the openness as part of your garden's journey. If you're worried, I recommend engaging a professional designer who can guard against both overplanting and overspending in your garden.

3) Lack of Variety

I love to walk—for my health and for inspiration—and on these walks, I see far too many residential gardens that rely on the same shrubs and perennials. So many boxwoods (don’t get me wrong, they have a place) and just not enough variety! While there's nothing wrong with reliable plants, limited variety misses opportunities for greater beauty and ecological benefits. When planning your garden, consider variety when it comes to:

Seasonality: Include plants that shine in different seasons—spring bulbs bursting after winter, summer perennials at their peak, fall foliage ablaze with color, and winter elements providing structure.

Color: It’s a given you’ll be working with green, but what other colors can you introduce through either flowers or foliage?

Shapes: Look for plants with leaves or flowers of different shapes. For example, flowers on spikes (like salvia or veronica) vs. flowers with petals (like coneflowers). Or plants that grow upright vs. in a mound or clump. 

Resilience: Diverse gardens withstand disease and pest pressures better than monocultures (that is, a single variety of plants).

Making intentional choices that create variety will ensure you love your garden all year long. One of my most successful client gardens features native shrubs as the backbone, four-season perennials providing contin uous color, ornamental grasses adding winter interest, and strategic spots for seasonal annuals. This thoughtful diversity ensures the landscape never appears static or lifeless, regardless of when you visit.

4) Improper watering

Water management remains the most common yet least understood aspect of gardening. Last summer's extended drought (which lasted into autumn) throughout Evanston and Chicago put a lot of stress on new gardens (and their homeowners). Here are a few things we can do to avoid irrigation issues:

The finger test: Insert your finger about an inch into the soil—if dry, water deeply; if moist, wait.

Deep but infrequent: Water thoroughly but less often to encourage roots to grow downward.

Target the roots: Direct water to the root zone rather than spraying foliage, which promotes fungal issues.

Timing: In the heart of summer, water in the early morning or evening. Water will evaporate off plants quickly in the mid-day heat and sun.

Mulching: Apply 2-3 inches of mulch to retain moisture, regulate soil temperature, and keep weeds at bay.

Hydro-zoning: Group plants with similar water needs to prevent over or under-watering.

Efficiency upgrades: Consider soaker hoses or drip irrigation for targeted watering.

A good rule of thumb is to make sure your established garden receives one inch of water per week. A simple rain gauge can help you measure rainfall and whether supplemental watering is needed. Keep in mind newer gardens (under 2 years) will need more than this. That’s why the finger test is always a good starting point.

5) Pruning at the wrong time

Nothing diminishes garden potential more quickly than improper pruning. I learned this lesson with my shrubs (viburnums) that got way too big. I foolishly trimmed them back in the fall, removed most of the flower buds, and was rewarded with plenty of foliage, but barely any blooms come the following spring.

I often hear that pruning can be confusing. This is why I created this list of quick tips to help you cut wisely 

Spring bloomers: Lilacs, forsythia, and viburnums form buds during the previous summer/fall—so prune immediately after flowering.

Summer stars: Roses, spiraea, and some hydrangea varieties bloom on "new wood"—these summer flowering shrubs can be pruned in late winter/early spring.

Evergreen care: Best pruned in early spring before new growth emerges.

Ornamental grasses and perennials: Cut back in late winter/early spring before new growth appears.

When in doubt about when to prune, research the specific plant or simply observe its flowering cycle for a season before making major cuts.

Remember, gardening is a journey that rewards patience. Every successful gardener has a history of withered plants and design missteps behind them! The difference is in learning from those experiences rather than repeating them. My own garden serves as a living record of lessons learned—including areas where I once struggled with poor plant selection and others where I finally achieved the right balance of variety and spacing.

When I walk through my clients' gardens, I see not only plants but stories of adaptation, persistence, and growth. I hope these five insights help you write a more joyful garden story. If you need guidance specific to your landscape, my door is always open for consultation.