outdoor home garden

Common Outdoor Plant Problems

Dealing with Common Garden Problems

When you have an outdoor garden, there are several diseases that could affect your plants. Learn to identify symptoms and respond with safe, effective treatment so that your plants thrive no matter what. Check out this guide to common plant problems and their solutions from Patio Growers to get started!

Black Spot

This common garden problem is typically found in roses, but it can appear in  other garden plants. Keep an eye on the leaves closest to the ground during extended wet periods, and you’ll catch these round black spots on the upper part of the leaf before they cause any real damage. In severe cases, infected leaves will turn yellow and fall off.

How to Control Black Spot

The best way to control this common plant problem is with well-draining soil. Some other tips include:

  • Provide regular fertilizer feedings
  • Remove dead leaves and prune infected areas right away
  • Use disinfected pruners and sheers every time
  • Water the roots, never the leaves

Black spot is only one type of fungal leaf disease. Other leaf spots thrive in similar conditions and can be prevented with the above tips. 

Powdery Mildew

powdery mildew on plant leaf

Another fungal disease, powdery mildew is a common garden problem that affects nearly every plant, including flowers, vegetables, landscape plants, and fruit. You’ll recognize powdery mildew by the white, powder-like coating on plant leaf surfaces, stems, flower buds, and fruit. Powdery mildew is usually caused by low soil moisture and high humidity on the plant surface.

How to Control Powdery Mildew

The best way to prevent powdery mildew is to make sure you’re not bringing it to your garden from an outside source, like a new plant. Once your plant is infected, follow these tips:

  • Remove infected debris and plant parts
  • Dispose of the infected materials away from your garden and compost pit
  • Space your plants far apart for more circulation that reduces humidity
  • Keep plant leaves dry
  • In severe cases, use fungicide

These tips will help with most mildew types, except for downy mildew. This disease is misnamed because it’s actually more similar to algae and not mold. Downy mildew looks a bit cotton-like and requires water to survive and spread to other plants.


Arguably the most common plant problem, blight often affects potatoes and tomatoes but can also be found in other plants. Blight spreads during warm, humid conditions through windborne spores and can infect your entire garden rapidly. 

How to Prevent Blight

There is no cure for blight, only prevention. Follow these tips to keep your plants as healthy as possible:

  • Grow early varieties of potatoes and tomatoes, as blight is strongest in mid-summer
  • Choose blight-resistant veggies, like Sarpo Axona or Sarpo Mira
  • Practice good plant hygiene with frequent pruning
  • Destroy all blight-affected plant parts and keep your garden clear of diseased debris
  • Dispose of blighted plant parts in the trash, never in the compost or around other areas of your garden


If you see open wounds on your plants, you probably have canker. This common plant problem is caused by fungal or bacterial pathogens in weakened plants and can range in severity. You’ll most likely see canker in woody plants with such symptoms as swollen or cracked areas on limbs and trunks. 

How to Control Canker

Removing the diseased parts during dry weather is a good start. You should also take the following steps:

  • Growing canker resistant plants
  • Avoiding overwatering and crowding
  • Preventing mechanical wounds from maintenance tools
  • Protecting young plants from sunscald
  • Maintaining appropriate nutrition levels in the soil

Are you ready to tackle these common plant problems in your outdoor garden setup? Find more guidance when you explore our blog!