What characteristic is common among the plants listed in the questions?

The choice indicating that all the plants are ornamental garden plants highlights a commonality that often connects their use in landscapes and gardens. Ornamental garden plants are valued for their aesthetic appeal, which includes attractive flowers, foliage, or form, thereby enhancing the visual aspects of gardens and outdoor spaces. This classification includes a wide variety of plant types, including perennials, annuals, and even some shrubs, which are specifically cultivated for ornamental purposes.

Understanding this characteristic allows horticulturists to make informed decisions on plant selection based on aesthetics, growth habits, and compatibility with other garden elements.

The other options may describe certain groups of plants, but they do not necessarily apply to all the specified plants. For instance, being native to Washington State might only apply to specific species, and not all ornamental plants fall under this category. Similarly, while some ornamental plants can be annuals, the group may also include perennials and biennials. Additionally, not all ornamental plants are aquatic; many thrive in well-drained soil environments rather than water. Therefore, selecting the option that indicates they are all ornamental garden plants captures their main function and purpose in horticulture.