11 Jun

The Right Plug

By Karen Villalobos

Not all plants grow the same, and not all crops require the same starting material. From vigorous perennials to deep-rooted native grasses, understanding growth habits can help guide plug selection!

Plug Size Matters 

Selecting the right plug size is one of the first decisions growers make when planning a crop. While all plug sizes are designed to produce healthy, successful plants, each offers unique advantages depending on the species, production schedule, and intended use. Understanding how different plants grow can help growers choose the starting material that best aligns with their production goals. 

Every Plant Grows Differently 

Not all perennials establish at the same rate. Some quickly develop roots and top growth after transplanting, while others build the foundation that supports long-term performance. 

Consider the difference between Phlox paniculata 'Jeana' and Baptisia australis. While both are exceptional landscape plants, their growth habits are very different. 'Jeana’ rapidly develops top growth and fills out during production, while B. australis invests heavily in root development before producing substantial above-ground growth. Understanding these natural differences helps growers select the starting material that best aligns with their production goals.

Flexibility 

Some perennials establish quickly and can perform well from multiple plug sizes depending on the grower's timeline and finishing goals. 

Plants such as Phlox paniculata 'Jeana', Monarda bradburiana, Calamintha nepeta 'Triumphator', Lysimachia lanceolata 'Burgundy Mist', and Aster oblongifolius 'Twilight Sky'™ are vigorous growers that readily establish after transplanting. These crops can be successful from a range of starting sizes, allowing growers to choose the plug that best fits their production schedule. 

For growers with a longer production window, smaller plugs may provide ample time for development. When a larger, more mature finished plant is desired on a shorter timeline, larger plug options can help achieve that goal. 

Additional Root Development 

Other species naturally take more time to establish and often focus their energy below ground before producing significant top growth. Plants such as Baptisia australis, Amsonia hubrichtii, and Pycnanthemum muticum are known for building strong root systems early in production. These species reward patience with exceptional durability and landscape performance, and growers often appreciate the flexibility that larger starting material can provide. Understanding the natural growth habits of these crops can help growers align plug size with production timelines and finished product goals. 

Grasses Have Their Own Timeline 

Warm-season native grasses frequently follow a different growth pattern than flowering perennials. Many spend their early stages developing extensive root systems before producing substantial top growth. Species such as Schizachyrium scoparium, Andropogon gerardii, and Sorghastrum nutans may appear slower early in production compared to some herbaceous perennials. However, this investment in root development contributes to the durability, drought tolerance, and longevity that make these grasses valuable landscape performers. 

Depending on the production schedule and container size, growers may find that different plug sizes help support their desired finish. 

Sedges and Ferns 

Many sedges and ferns are prized for their adaptability and longevity, but they often establish differently than flowering perennials. 

Species such as Carex amphibola, Carex cherokeensis, and Carex pensylvanica develop strong root systems that support long-term performance in the landscape. Likewise, ferns such as Polystichum acrostichoides and Dryopteris marginalis typically mature at a more measured pace than many flowering crops. Selecting the appropriate plug size can help growers match these unique growth habits to their production objectives. 

The End Goal 

When choosing a plug size, it can be helpful to start with the finished product in mind. Questions to consider include: 

  • What container size will the crop finish in? 
  • What production window is available? 
  • How quickly does the species establish after transplanting? 
  • What level of maturity is desired at sale? 
  • Is the crop known for rapid top growth or extensive root development? 

The answers often help decide which plug size is the best fit for a particular crop. 

A Tool 

Rather than thinking of one plug size as universally better than another, it's helpful to view each size as a tool designed for specific situations. A vigorous perennial may thrive from several different starting sizes depending on the production schedule. A slower-establishing native grass may benefit from a different approach. The key is understanding how the plant grows and selecting the plug size that best supports the desired outcome. 

Whether growing a quick finishing perennial, a deep-rooted native grass, a woodland sedge, or a long-lived fern, matching plug size to crop characteristics helps set the stage for success from transplant through finish. 

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