The nomenclature of these plants can seem confusing. The species include Nepeta grandiflora, N. sibirica, N. faassenii, N. subsessilis, and what have you. And the common names are equally confusing: are they catmint or catnip? The answer is, it depends. Sometimes the same plant is called by different names. But the important thing for most gardeners is the actual plant.
One of the most versatile is Nepeta x faassenii 'Snowflake'. It can be used as a pretty specimen, as a grouping, and an edging plant. Only 14 inches high, and about 12 inches across, with snowy white flowers, it is refreshing. I have found that it has a tendency to wind itself around other plants, providing a non-invasive ground cover that smother weeds. Left alone, it will form a beautiful backdrop to your other plants without smothering them. With green gray foliage that appears quite early in spring, and with the ability to re-bloom without deadheading, it has become a staple in my garden.
Nepeta grandiflora 'Dawn to Dusk' is not commonly seen in American gardens, but this selection of nepeta is beautiful enough to serve as a specimen, a plant for the middle of the border, and is a superb accompaniment to other shrubs, replacing geraniums. It has sturdy stems, soft pink flowers and an upright habit. About 23 inches high and wide, it is another nepeta that re-blooms regularly if deadheaded and, if desired, you can it back by half to completely rejuvenate it. I love putting it beside the Canadian Explorer rose 'Morden Blush'.
Nepeta subsessilis 'Sweet Dreams' is also pink but distinguishes itself by presenting dark burgundy floral bracts against large deep green leaves - leaves larger than most nepeta. 18 inches high and about 30 inches wide, it has the same long blooming season as other more traditional nepeta.
If you would like to try an uncommon and very lovely blue nepeta, I can recommend Nepeta sibirica 'Souvenir Andre Chaudron'. A somewhat compact cultivar, it grows to about 18 inches tall, and it has numerous two lipped medium to deep violet blue flowers on top of square leafy stems. It is also sold as 'Blue Bedder'. Nepeta sibirica is also available as seed, and is very easily grown. I obtained the seeds and grow it to accompany my roses.
A few tips for those new to growing Nepetas:
1. Take it easy on the fertilizer. Indeed, these plants don’t require any, and if you provide it, some of them can become floppy.
2. In terms of care, just cut them back after bloom if you want them to bloom all season.
These beauties can be placed under and around your roses, peonies, shrubs or establish them as stand alone specimen plants. Or, of course, you can also group them. It all works. Adding one or more of plants to your garden will result in ease of maintenance, while adding distinctiveness to your garden. So this summer, give Nepetas a try...no matter what you call them.