Perennial Solutions: Nepeta ‘Purrsian Blue’
Nepeta ‘Purrsian Blue’ is the perfect cultivar for those seeking a tidier, more compact catmint. In addition to its attractive plant habit, ‘Purrsian Blue’ was selected for being highly floriferous. Bred by Walters Gardens Inc., this cultivar has great potential.
‘Purrsian Blue’ has aromatic, silver green foliage, which forms attractive, naturally rounded clumps growing 14 to 18 inches high and spreads 18 to 30 inches across at maturity. It begins to flower in the late spring and continues blooming throughout the summer until the fall frosts arrive. This floriferous cultivar produces tons of periwinkle blue flowers with dark purple calyxes.
Nepeta are widely used in sunny landscapes with average to slightly dry soils throughout Zones 3 to 8. They are somewhat intolerant of the heat and humidity of the deep South and should be grown in afternoon shade in these climates.
‘Purrsian Blue’ is an easy-to-grow, low-maintenance perennial that is well suited for today’s landscapes. Hummingbirds, honeybees, butterflies and other pollinators are drawn to its sweet nectar while its spicy fragrance keeps rabbits and deer away.
Propogation
Nepeta ‘Purrsian Blue’ is vegetatively propagated by tip cuttings by licensed propagators; unlicensed propagation of this cultivar is prohibited.
Licensed propagators root tip cuttings by sticking them directly into a pre-moistened, well-drained growing mix or stabilized growing media. Catmint roots readily and does not require rooting compounds to propagate them successfully. Place the cuttings under a moderate misting regiment for about the first two to three days of propagation. After the first few days, decrease the amount of mist being delivered each day to provide light misting for the next several days. When possible, it’s best to propagate them under high humidity levels (90 percent relative humidity) with minimum misting.
It’s beneficial to begin feeding using 100- to 150-ppm nitrogen using a complete water-soluble fertilizer two times per week beginning seven days after sticking the cuttings. The mist can generally be removed altogether at 12 to 16 days after sticking, once a reasonable amount of roots is present and the cuttings can remain turgid throughout the day. With soil temperatures being maintained at 68 to 74o F, they will usually be well rooted in three to four weeks.
Production
‘Purrsian Blue’ is well suited for production in one gallon or smaller sized containers. They prefer to be grown in a well- drained growing mix with the pH maintained between 6.0 and 6.6. Many growing mixes will suffice; however, avoid ones with high water-holding ability. At transplant, plant a single liner in the center of the pot with the soil line of the liner even with the growing medium of the container it’s transplanted into.
Catmint have light to moderate fertility requirements. When using water-soluble fertilizers to deliver nutrients, apply 100- to 125-ppm nitrogen plus micronutrients with every irrigation or 250 ppm as needed. Fertilizing them too heavily will result in some elongation, a lush appearance and delayed flowering. Controlled-release fertilizers can also effectively deliver nutrients when incorporated into the growing medium prior to planting at a rate equivalent to 0.9 to 1.1 pounds of elemental nitrogen per cubic yard of growing mix or applied as a top-dress onto the media surface using the medium labeled rate.
Nepeta can be grown under average irrigation regiments. The plants should be kept slightly moist, but not saturated or consistently wet during production. They will grow taller and are more prone to root rot pathogens when they are kept too wet. When irrigation is necessary, water them thoroughly then allow the soil to dry slightly between waterings.
With its compact growth habit, ‘Purrsian Blue’ does not usually require height management strategies. Undesirable stem elongation can often be managed by providing adequate spacing between the plants, growing them under high light levels and with the appropriate (not excessive) nutrient and moisture levels.
If the plants need to be toned, apply spray applications of 30- ppm paclobutrazol (Bonzi, Paczol or Piccolo), 5-ppm uniconazole (Concise or Sumagic) or the tank mixture of 2,500-ppm daminozide (B-Nine or Dazide) plus 3-ppm uniconazole. In most instances, one or two applications will be sufficient.
Pests and Diseases
Nepeta can be produced relatively free of insects and diseases. Occasionally, aphids, leafhoppers, slugs, snails, spider mites and whiteflies may appear causing only a minimal amount of crop injury. Crown and root rots may develop when they are grown under consistently moist growing conditions. Other diseases to look for include Botrytis, bacterial leaf spot (Pseudomonas), powdery mildew and Southern Blight (Sclerotium).
Routine scouting will allow for early detection of these pests and diseases and can be useful to determine if and when control strategies are necessary.
Temperatue and Scheduling
Flowering plants of ‘Purrsian Blue’ can easily be achieved throughout the year. They do not have a vernalization requirement for flowering, but will flower more uniformly and slightly faster when a cold treatment is provided. Provide six to nine weeks of cold (less than 40° F) when vernalizing nepeta liners or containers. They are long day plants and must be grown under long day lengths in order for the flowers to develop. When the days are naturally short (less than 14 hours), long day lengths can be provided using photosynthetic lighting (night interruption or day extension). When they are grown at 65° F, they will flower in approximately eight weeks from the onset of long day lengths.
Availability
Nepeta ‘Purrsian Blue’ is exclusively available from Walters Gardens Inc. Currently, they are available in 72-cell liners or from bare root.
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