Part 2 of our coverage of the 2023 California Spring Trials looks at some powerful perennials
July 31, 2023 By Rodger Tschanz
The new perennials showcased at CAST 2023 mostly have one thing in common and that is the ability to have great ornamental value in the first year. Many of the perennials are being tested under Zone 5 or lower winter conditions to evaluate true perennial potential. Many of the plants highlighted here have been tested for winter hardiness to at least a USDA Zone 5. In the few instances I have mentioned less winter hardy perennials, it is because of their unique appearance and/or great ornamental potential as an annual.
Double Scoop Deluxe Series of Echinacea
The Deluxe Double Scoop series (1) is an improvement in branching and flower number over the traditional Double Scoop series. The production timing is like the Sombrero series. It is compact, reaching garden heights of 50 to 60 cm and has reliable first-year blooming habit. Colours currently include: Orangeberry, Raspberry, Strawberry, and Watermelon. (Zones 4a-9b)
Silver foliage plants
On display at CAST was a collection of three silver-leafed species that were selected primarily for the ornamental value of their foliage. Silver Scent Salvia (Zones 5a-9b) is a selection of garden sage (Salvia officinalis) with both attractive foliage and purple spring flowers. Little Lamb (Zones 4a-8b) is a selection of Lamb’s Ear (Stachys byzantina) with fine, decorative foliage and shorter flower stalks than is the norm with this species. Silver Swirl Centaurea (2) (Zones 6b-9b) (Centaurea ragusina) may be less winter hardy than the first two selections but has showy silvery white leaves with a wavy edge. It has a compact habit reaching heights of 28 cm.
Dreameria Vivid Dreams Armeria
This is a new, deep purple colour (3), for this series of sea thrift (Armeria pseudarmeria). It is suitable for containers and the landscape with heights reaching 30 cm. It has great heat tolerance and hardiness of Zones 5a-9a.
Emerald Crest Caryopteris
This compact, pollinator friendly selection (4)(Zones 8a-9a) of Caryopteris x clandonensis blooms late in the summer providing a blue floral option for the garden’s fall colour palette. Garden heights can reach 91 cm.
While no new seed propagated perennials were announced from Kieft Seeds, both Kieft and Darwin Perennial selections are included in a new online tool (FYF) for first-year flowering perennials. If you know what week you want to see colour on your Kieft/Darwin perennials, the tool will help you schedule the rest of the production.
Selecta One is busy testing winter hardiness on its dianthus breeding and there are sure to be new Zone 5-hardy plants announced in the future. For the coming year they have the new Pashmina series (5) which is said to be hardy to USDA (Zone 5a). It is a fast- crop perennial for spring sales that does not require vernalization. It blooms from spring to summer and is currently available in red, magenta, and pink/white bicolour. Garden heights can reach 30 cm.
For the rock garden, Benary has a new pink selection of its series of Arabis caucasica, Catwalk (6). Joining a white already in the series, Catwalk Pink has a compact uniform, rounded habit. No vernalization is needed to induce bloom. As such it is a great fit for spring production. In addition to the rock garden, it is suitable for container gardening. (Zones 3-7)
The Lewisia cotyledon, Elise Golden Yellow is another great choice for the rock garden, containers and other beds. It is also a first flowering with out vernalization plant. It is heat and drought tolerant and has a long flowering season. Other colours in the Elise series, include white, ruby red, violet and a mix of at least five colours. Ruby Red and the Mix are Fleuroselect Gold Medal winners. (Zones 3a-8b)
For the pollinator garden, there is a new Lavender angustifolia ‘Chill-Out Blue’. It is first year flowering without vernalization, has a compact, well branched habit reaching heights of 25 cm. The intensely blue flowers are strongly attractive to pollinators. For the greenhouse grower, this plant has reliable germination. This cultivar is well suited for pot production. (Zones 5a-9a)
The PollyNation series of multi-coloured echinacea has added pink-shades to the collection of individually coloured seed lots of white, orange-red, magenta and yellow. First-year flowering without vernalization, well branched, this compact plant is suitable for patio containers and the landscape. (Zones 4-9)
Solidago Spark Plug (7) is the first day-length neutral goldenrod. As such it can be finished early in the season for spring and summer sales. It can reach garden heights of 60 cm.
Lupine Staircase White is a new addition to the Staircase series. This series is said to be the only day-length neutral perennial lupine that requires no vernalisation. Garden heights reach 90 cm. (Zones 4-8)
Salute series Salvia
Dümmen Orange continues to add to its extensive list of Salvia nemorosa introductions (8). New this year is a new neon pink colour for the Salute series – Neon Pink and Dark Blue. Together with the colours already in circulation, this series has the full range of possible colours. The light pink, white and Ice Blue colours are well matched for timing and can be used together in a Confetti Garden-type of application. This series is very attractive to bees. (Zones 3-9)
Noble Knight Salvia
A new, stand-alone salvia is Noble Knight. Its large flower size and dark contrasting foliage has caught the attention of retailers at early trials. More colours will be coming. To prevent stretching in production, grow cool, using pansy cultural recommendations. (Zones 3-9)
Another standalone release is the salvia, Noche (9). It has very colourful calyxes and stems. Even when not blooming it appears to be blooming. In addition, it is heavily branched; with salvia, the more branches mean more bloom, so it is also a heavy bloomer. (Zones 3-9)
The last Salvia release for this year is Caramia Rosa(10). Approximately five years ago, the original purple Caramia was released. This series is a vigorous grower and a great candidate for the landscape. In trials in the Netherlands, this plant returns year after year reaching heights of 75-100 cm. While the Salute series, Noble Knight and Noche are best produced in a 1-gallon pot size, the Caramia series is a candidate for three- to five-gallon culture. (Zones 3-9)
Candela is a new series of veronica (11). It is available in hot pink, pink, purple and blue colours. While no veronica series matches perfectly, this series is close when grown under identical conditions. No vernalization or other special treatments are required to initiate bloom. Expect a mid-June bloom date. (Zones 5-9)
Candy Sorbet iberis
Candy Sorbet is a brand new iberis that has a very late bloom date. In southern Ontario it will start to bloom in late June and continue through until late August or early September. It is important to note that instead of white, expect a pink bloom colour with this cultivar. (Zones 6-9)
The new series of agastache, Honeysticks,(12) is said to be hardy to zone 6. It has a vertical growing habit. The phrase “flower on a stick” has been used to describe its bloom habit and pollinator attraction trait. It is currently available in purple, orange, and yellow colours. (Zones 6-9)
Zasha (13)is a new compact Russian sage that grows with an upright habit.The compact Perovskia, Jelena was released last year but it has a mounding habit in comparison. Zasha blooms approximately three weeks earlier than has been normally expected with Russian sage. (Zones 4-9)
New colours have been added to the Zone 3 hardy SpinTop gaillardia lineup. This series is tolerant of high summer humidity as well. SpinTop Red Starburst Improved (14)has bright yellow petals with a red wine-coloured centre. The SpinTop Mariachi series has tubular petals. The new Mariachi Red Sky colour (15) has red tubes tipped with orange.
GoldiPhlox – Syngenta
There are three new additions to the GoldiPhlox (16) series: light pink, lavender eye (a replacement for light blue), and an improved pink. This series represents some of the newest breeding being done on Phlox subulate with improvements all due to lovely dark pigmentation, large bloom size and increased branching. (Zones 3-9)
Alpino Early – Syngenta
Alpino Early (17)is a series of Saxifraga arendsii that blooms two to four weeks earlier than the Touran series. The three new colours in the series include: Carnival Improved, Deep Red (a replacement for Carmine) and Early Rose Improved (18). All of these have improved flower form, extra branching, and larger bloom diameter than is commonly found. There is also an improved white; altogether there is better uniformity between the colours. The plants I saw blooming on display in California in late March looked great and had already been blooming for three months. (Zones 4-9)
Erysistible erysium – Syngenta
The new Erysistible series of erysimum (19) has a winter hardiness of Zone 5. It is best grown cold for early spring sales. Full vernalisation is not necessary to initiate bloom but growing cool will help unify the bloom times and improve habit. Expect periods of bloom lasting greater than three months under cool growing conditions. Colours include yellow, magenta, tricolor, yellow-pink and bronze-rose. Novelty colours that are hardy to Zone 5 are unique.
Prairie Blaze echinacea – Syngenta
The new Prairie Blaze series of Echinacea is the first OP seed type available in novelty colours. These include golden yellow, green, orange sunset and vintage lime. This series is first year flowering and has a compact growth habit. It is suitable for growing in containers and the landscape. (Zones 3-9)
Guatemala Gold – Danziger
Panama Red, introduced in 2022, was the first echinacea propagated from cuttings; the new Guatemala Gold is the second. It has sturdy stems, a compact habit and blooms close to the foliage. It reaches garden heights of 30 cm. (Zones 4-9)
Pink Nebula – Danziger
The purple Dark Matter selection of Salvia nemerosa now has a pink companion named Pink Nebula (20). It has Dark Matter’s compact, well-branched mounding habit and intense bloom colour that contrasts well against the foliage. (Zones 4-9)
Solanna coreopsis – Danziger
A new bicolour has been added to the Solanna series of coreopsis. Sunset Bright (21) has semi-double blooms with golden yellow petals and a large central wine-coloured patch. Like other cultivars in this series, it has large bloom diameter, a compact mounded habit and a first-year bloom habit without the benefit of vernalisation. (Zones 4-9)
Layla Presto Blue – Danziger
The new addition to the Layla series of Lavandula angustifolia, Layla Presto Blue has excellent branching and blooms up to 10 days earlier than Layla Blue. It does not require vernalisation to bloom, flowers spring through summer, and is pollinator friendly. (Zones 5-9)
Pink Pearl agastache – Terra Nova Nurseries
The new agastache, Pink Pearl has great mildew tolerance and increased hardiness. Its habit is compact and mounding with large flower spikes. The two-toned flowers are large, dense and cover the entire canopy of the plant. (Zones 6-10)
I want to thank Greenhouse Canada magazine and Ball Horticultural for supporting my travel and hosting me on my visit to CAST 2023.
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