Iceberg Roses Have Holes in Their Leaves

Q. I am growing iceberg roses and have noted holes in the petals of the flowers. I have taken this problem to nurseries, and they are stumped. Do you know what causes this?

Iceberg roses with holes in the flowers.

A. The shape of the damage to the petals can give some clues. If the shape is circular and smooth, or near circular, then it is probably damage from a leaf cutter bee. These bees cut holes from flowers that are nearly circular and about the size of a dime. They are great pollinators when they are active.

Holes Due to Leaf Cutter Bees

            Since these are solitary bees and the female cuts these circles for egg-laying, they start showing up when it gets warm, in about April and then through the summer. That’s why they make good pollinators for apples, pear or other late or continuous bloomers. You will not see these near perfect circles show up until that time. If the holes have jagged edges around their outside, then most likely it's a chewing insect or possibly snails/slugs.

Leaf cutter bees make nearly perfect circles or near circles in leaves and flowers of plants like this pepper leaf.

Holes Due to Slugs or Snails

            You will have to do some detective work if the holes are not from leaf cutter bees. Snails and slugs are the easiest to detect because they'll leave a slimy trail on leaf undersides when they do their damage. If you think its snails or slugs, then spread out wet newspaper or cardboard just before nightfall. They like darkness and moisture. so, the dark and moist undersides make perfect traps. Squeamish fingers will pluck them from this underside for execution.

Slugs or snails can leave holes in leaves but usually leave a slimy trail behind. The browning of these lettuce leaves is wilting damage as well.

Sticky Traps

Sticky trap in greenhouse for insect trapping.

            If it’s not snails or slugs, then make or buy sticky traps. These can be made by hanging yellow sticky 4” x 6” business cards close to the damage and covering them with a sticky substance. Smeared Vaseline jelly will work but not Vicks!