I have 3 Yucca plants in my yard. Two are growing nicely, but only one produces a flower stalk. One has not grown at all since being planted 3 years ago, but does not show signs of pests or over/under watering. How can I get the small one to grow -- I have tried Miracle gro. How can I get all of them to produce a flower stalk?
Fertilizing might help, but typically yuccas don't need a lot of fertilizer. You may want to check the soil, or even have it tested, to see what, if any nutrients may be deficient in that particular spot. You may also try a balanced fertilizer once every 3-4 months.
Yuccas bloom intermittently. It is just a waiting game and there is not much that can be done to make them bloom. That said, you could try inducing blooms by adding phosphorus, such as bone meal, to the soil around your plants. Here is more information on yucca blooming: https://www.gardeningknowhow.com/ornamental/foliage/yucca/yucca-plant-doesnt-bloom.htm