Thank you for your lemon cucumber question. There are a variety of things that could be causing your plants to have foliage and no blossoms.

The first blossoms often drop from the vines. This is not a problem, since the first flowers to appear on the vines are male. The female flowers, which open later, have a swelling at the base that forms the fruit, also known as the ovary. After bees pollinate these female flowers, the fruit develops. Source: Growing cucumbers in home gardens | UMN Extension

If you are not getting bees in your garden, pollination will not occur. For example, keeping your plants covered can impede the bees getting to your plants.   Also, hot weather can cause flowers to drop.  Bees may not visit your garden as frequently, as they do not prefer hot weather. Finally, too much fertilization can create a lot of foliage and impede blossom development.

Given our recent very hot temperatures, the following article provides information that you may find helpful: Heatwave makes vegetables misbehave | UMN Extension

For more information, I recommend you contact the Plant Clinic at the OSU Deschutes County Extension in Redmond. You can call the phone number listed below or send your question and photo to <personal data hidden>

The person on duty will review your information and contact you with findings or management options.

Summer Hours: Monday through Thursday, 9:00 to 5:00 pm, Friday 9:00 am to 1:00 pm.

Phone:<personal data hidden> x79630

We always welcome your home garden questions at the OSU Plant Clinic.