The nursery industry sells plants in a huge variety of pot sizes. This is further confused by our habit of referring to pots using mm, inches or even Litres! To make matters even more interesting, a single plant may spend time in up to 4 pot sizes before it reaches you.
Let’s simplify this for you... at Buedale we sell our grasses and strappy leafed foliage plants in 2 sizes only – Viro-tubes and 140mm pots. In the past Bluedale has sold plants in Viro-cells (also called plugtrays), however we found results to be frequently disappointing and we no longer recommend them for direct planting in landscapes.
So Viro-tubes or pots? Choice largely depends on factors such as character of the species itself, project goals, available aftercare and budget. Choosing correctly will improve the outcome of your planting project. Bluedale are obviously very happy to assist you when making choices on pot size, however a crash course in plant pot sizes will not do the discerning gardener, landscape designer, revegetation officer or contractor any harm!
These are 50x50x90mm tubes in trays of 50 and are without doubt, the best way to grow Grasses, Strappy Leafed Plants, Sedges and Wetlands Plants. The unique design of the Viro-tube works to prevent plants from becoming root bound by training downward root growth to an open base where roots are air pruned. Viro-tube grown plants establish quickly as their roots don’t have to fight their way out of their own root ball. In fact the roots are primed ready for fast establishment.
Viro-tubes are often preferred for revegetation projects. High planting densities can quickly result in thick swathes of grasses outcompeting weed species while perhaps fulfilling an ecological role.
Viro-tube planting rates vary with species, but generally for most mass planting applications rates of 5 to 7 plants per square metre are appropriate. At $1.00 - $1.20* per tube (PBR varieties $1:85 - $2.10*) this equates to $5.00 - $8.40* per square metre (PBR varieties $9.25 - $14.70*). This is substantially less expensive than purchasing 140mm pots. In addition, due to their relatively small size, Viro-tubes can be planted quickly. It is not uncommon for specialist contractors to plant 2 to 3 thousand Viro-tubes per day per person!
There are a few more things to consider before you select Viro-tubes. Appropriate before and after-care is vital for success. Soil preparation prior to planting is necessary to ensure the Viro-tube root ball does not find itself surrounded by air pockets or impenetrable clay – both of these scenarios will dramatically reduce success. Also regular and frequent watering is paramount. Viro-tubes only penetrate 90mm into the soil and as such get hot and dry very quickly-choose your planting season carefully to avoid a high watering burden. On a final note – bushland wildlife enjoy grazing on fresh plants brought to them direct from the nursery. Ducks, kangaroos, possums etc can easily pull Viro-tubes out of the ground. Perhaps a ‘trial’ small scale planting will determine how problematic predators on your site are likely to be.
Also referred to as 6” or 2.5L pots, 140mm pots are ideal for landscaping projects, commercial applications and roadsides. They are 140mm deep with a 125mm diameter. Plants grown in these pots have a larger root ball than their Viro-tube cousins and in many ways this makes them more forgiving.
As for Viro-tubes, pot planting rates vary with species and application. For mass planting, rates of 3 to 5 plants per square metre are common. At $3.95 - $5.95* per pot this equates to $11.85 - $29.75* per square metre, over double the cost of Viro-tubes. They are also slower to plant, requiring a hole 190mm in depth (1/3 larger than actual pot size).
140mm pots are ideal for areas where an instant plant presence is required. Examples include domestic and commercial landscapes, public parks and gardens and roadsides. Plants are more established in 140mm pots and grasses grown in this size pot can be quite tall.
Watering requirements are less for 140mm pots and they can be easier to mulch around. Provided appropriate care is given, high survival rates can be expected.
Although Bluedale does not recommend plants in Viro-cells for direct landscape planting, we use them in our production process. Other nurseries continue to supply them to landscape and revegetation contractors, as we have done in the past. We feel it is important that our clients be aware of the pitfalls associated with planting cells directly into the landscape.
Cells are 25x25 x45mm compartments in rigid trays of 162. Their root ball is 12% of the volume of Viro-tubes – now that’s small. Our experience with cells is that they dry out quickly, often on the way to site. Associated losses can be significant. Further, predation by birds, possums, rats or whoever wants a cheap feed can be significant as the cell is easily pulled out of the ground. Success requires exceptional soil preparation and a rigorous watering regime which is time consuming and more often than not, impractical.
*Prices are a guide only and vary with species, numbers purchased etc. Bulk discounts have not been applied to these prices.