I have always been a fan of smaller plants. For one, they are easier to stash in my car when I just need 10 more perennials. When I was starting new gardens at a park, where I had to carry all my plants in, quart size containers were preferred over lugging gallon pots.
Now I have a new reason to prefer plugs: ease of planting and the ability to add many multiples of the same plant. We are adding an extensive pollinator garden to our new location. In a more traditional garden, adding seven Rattlesnake Masters or five Rudbeckia Maxima would be sufficient. However, in this landscape that would not scratch the surface of what we need. I am looking at 20 or more of each plant. This is where plugs are ideal.
Plant Thick: I have beds where I planted some plugs a bit close. I'm planting with the assumption that some may perish this year or over the winter. Should they all survive and return next spring, I can simply relocate some plants.
Ease of Planting: Shuffling a tray of 32 or 52 plugs about a garden is far easier than lugging about gallon pots. The soil was turned and amended when we laid out the garden and walking paths so all I needed was a swift scrape with cobrahead tool to make an adequate planting site for a plug. Very easy.
Accelerated Growth: While the plugs are still smaller than the gallon plants we installed for instant impact and to define planting areas, some plugs have already reached a size that makes it difficult to discern if they were from a pot or a plug. Many are also blooming.
Planning for Growth: It may be difficult to plan for mature plant growth. We are accustomed to planting our gallon plants rather close together. With a plug that's only three inches tall, we have to remember that it may mature to five feet tall and three feet wide. Even if you are planting thick, and know you may need to relocate a few plants next season, take care to reserve space for the remaining plug to mature without encroaching too much on neighboring plants. Our end goal is a lush garden, not one that is smothering itself.
Patience: Some areas within the new landscape are nearly planted, but may look a bit sparse to the untrained eye. Even though many plugs have more than doubled in size already, in the following year they will be considerably larger. A bit of patience is required to see the garden fill in.