Plant of the Month for July, 2013

Corydalis nobilis

(kor-ID-ah-liss NO-bil-iss)

General Information:

Carl Linnaeus, famous for developing the modern scheme of binomial nomenclature, received some incorrectly labeled seeds that turned out to be Corydalis nobilis. Decedents of these plants can still be found today in his preserved garden. In fact it is an early example of a non-native plant escaping from a garden and becoming naturalized in its new home. It is believed that all of the wild Corydalis nobilis growing in Finland and Sweden are escapees from Carl Linnaeus’ garden.

corydalis nobilis main

Corydalis nobilis; photo by Robert Pavlis

Corydalis nobilis, also called the Siberian corydalis, is a very special plant. It is one of the largest corydalis, and it is a reliable perennial in northern climates. Once established, which can take a couple of years; it is a reliable bloomer in the garden.

coyrdalis nobilis closeup

Corydalis nobilis; photo by Robert Pavlis

The flower is the main attraction partly because it is yellow and bright, but mostly because it has such an unusual shape. The inflorescence is very dense with up to 40 flowers. Each golden yellow flower has dark violet marking. Flowers last 2-3 weeks and have a spicy fragrance.

corydalis nobilis extreme closeup

Corydalis nobilis; photo by Robert Pavlis

By mid-summer, the leaves have all died back, and the plant has gone underground for a rest allowing other later flowering plants to steal the show.

Life Cycle: perennial

Height: 60 cm (2 ft)

Bloom Time: spring

Natural Range: Siberia, Mongolia, China

Habitat: among shrubs, on rocky places, and in shady ravines

Synonyms: none

Cultivation:

Light: part shade to full sun

Soil: good drainage

Water: moist in spring, drier in summer

USDA Hardiness Zone: 3 - 8

Propagation: seed sown immediately, difficult by division in fall

Seedex availability (ORG&HPS annual Seed Exchange): occasionally

Germination Tips:

Sow immediately. The viability of these seeds is short or the species propagates best with fresh seed. Stored seed might be coaxed into germination with temperature cycling and patience.

Give sown seeds several weeks @ 20°C to imbibe water (perhaps even germinate!), then expose to fluctuating outdoor winter temperatures including freezing for 3 months. Gradually increase light and temperature in spring. See https://www.youtube.com/watch?v=SO_KKbGYTEM

Special Care:

does not tolerate dry storage; place in moist towels in June; needs oscillating temperatures of both fall and spring to germinate

Contributions to this page were made by: Robert Pavlis

Plant of the Month for March, 2013

Colchicum autumnale

(KOHL-chi-kum aw-tum-NAH-lee)

General Information:

The flowers look just like a crocus but only show up in the fall which explains its common name of autumn crocus. It is actually a Colchicum, a plant that is unrelated to the true crocus.

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Colchicum autumnale planted under an Hydrangea; photo by Robert Pavlis

The pictures are taken from plants that have been handed down without a name. They are probably one of the named varieties and not the true species.

Colchicum autumnale grows leaves in the spring, which then die down in early summer. The plant remains dormant underground until fall at which time leafless flowers appear. Each flower lasts only a few days, but a large corm can have up to 6 flowers which open over seveal weeks. Hybrids are available in a number of shades of pink, mauve and white. It is a refreshing flower to see at a time of year when most other plants are going dormant and brown.

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Colchicum autumnale showing spring leaves; photo by Robert Pavlis

Colchicum grow from corms (swollen stem). Although the plants are relatively expensive to buy, they quickly expand by forming new corms underground. After the leaves die down in mid-summer they can be dug up and divided every few years to increase the number of plants.

All parts of the plant are poisonous which may explain why neither squirrels nor deer bother this plant.

colchicum autumnale closeup 480x317

Colchicum autumnale; photo by Robert Pavlis

Crocus and Colchicum have very similar flowers except that Colchicum tend to be much larger. Crocus have 3 stamens and their leaves are narrow and grass-like and may have a white line down the center of the leaf. Colchicum have 6 stamens and the leaves are wide, a solid green and look more like leaf lettuce. Flowering time is not a sure way to distinguish between Crocus and Colchicum since both genus have spring and fall flowering species.

Selecting a good spot in the garden can be a bit tricky. They don’t fit into the rock garden very well because of their large leaves. The flowers are short and bloom in the fall, so you don’t want to site them beside plants that will grow taller and hide the flowers. I find that near the drip line of shrubs is a good location. They would also do well beside summer flowering perennials that are cut back in early fall.

Life Cycle: cormous perennial

Height: flower are 20 cm (8 in), leaves are 30 cm (12 in)

Bloom Time: fall

Natural Range: Western and Central Europe

Habitat: meadows and woodland clearings

Synonyms: none.

Cultivation:

Light: full sun, can take some shade

Soil: loam or sandy soil, that is dry in winter

Water: average moisture in spring and fall, dry in summer and winter

USDA Hardiness Zone: 4 - 9

Propagation: seed, division of corm offshoots

Seedex availability (ORG&HPS annual Seed Exchange): rarely (although other Colchicum species are normally available)

Germination Tips:

Requires soaking. Place in warm water until seeds swell, usually 24-48 hours. Discard floaters and the water used for soaking. See https://youtu.be/dhL57pqnHHQ

Special Care:

must have summer heat to germinate; may take 6 years to germinate; grow seedlings @ 4°C x 1 month

Plant of the Month for September, 2015

Clematis mandshurica

(KLEM-uh-tiss man-SHEU-ree-ka)

General Information:

An unusual clematis that forms a low bush of very fragrant flowers. Clematis mandshurica makes a great addition to your garden.

Clematis mandshurica; photo by Robert Pavlis

Clematis mandshurica; photo by Robert Pavlis

It is similar to C. recta, but flowers about 2 weeks later, on a slightly taller plant which starts to cling when it gets over 1 m tall. C. mandshurica has larger flowers which are more fragrant than C. recta. It is also similar to C. terniflora, the sweet autumn clematis, which blooms a month later on much taller plants and has a much stronger tendency to climb.

Some sources give it a variety status and name it Clematis terniflora var. mandshurica. C. mandshurica is also incorrectly spelled C. mandschurica and C. mandchurica.

Prune hard in spring (Group 3). The plant in the pictures is a first time flowering seedling about three years old and is about 120 cm (4 ft) tall.

Clematis mandshurica; photo by Robert Pavlis

Clematis mandshurica; photo by Robert Pavlis

Life Cycle: perennial

Height: 180 cm (6ft)

Bloom Time: mid-summer

Natural Range: China, Mongolia, Russia (Siberia) and North Korea

Habitat: dry slopes, shrubby areas, forest margins

Synonyms: Clematis recta var. mandshurica, (Clematis fusca var. mandshurica is a synonym for C. fusca)

Cultivation:

Light: full sun

Soil: well drained

Water: drought tollerant

USDA Hardiness Zone: 3– 9

Propagation: seed, division

Seedex availability (ORG&HPS annual Seed Exchange): occasionally

Germination Tips:

At one time, we advised "Tails may inhibit germination. Remove them." The advice applied primarily to pulsatillas and clematises. Our most recent data indicates that leaving the tails on has no effect on germination.

Sow @ 20°C for 6 weeks, then place @ 4°C for 6 weeks, then slowly raise temperature to 10°C for 6 weeks. If there is no germination, repeat the cycle. This mimics fall sowing outdoors for spring germination.

Contributions to this page were made by: Robert Pavlis

Plant of the Month for November, 2011

Clematis columbiana v. tenuiloba

(KLEM-uh-tiss man-SHEU-ree-ka)

In his talk on the flowers of the Western United States, Barrie Porteous highlighted Clematis columbiana var. tenuiloba. Just 15 to 28 cm (6 to 10") in height, with a sprawling growth habit, and native to areas of limestone rubble and cold winters, it is a highly desirable species for Ontario rock gardens. Like other alpine plants, it thrives under high ultraviolet radiation and drying winds. ORG&HPS member, Barry Parker observed that the one he planted outdoors in a trough was superior to his greenhouse specimen. Former member Rodney Shaver had success growing this plant at the base of a crevice garden.

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Clematis columbiana var. tenuiloba photo courtesy of Barrie Porteous

While the species flower is mauve, the selection 'Ylva'™ is darker and bluer. Henrik Zetterland of the Botanic Garden in Gothenburg named the latter after his daughter.

ylva in trough outdoors

'Ylva' outside in trough

Ylva in bud '

Ylva' in bud in greenhouse

'Ylva' photos courtesy of Barry Parker

Because it is challenging to get Clematis columbiana var. tenuiloba to bloom in cultivation and obtaining viable seed is even more difficult, you will rarely find seed offered through our Seedex. Propagation from seed will produce plants identical to the parent species. Seed should be sown while it is still fresh in a very well-drained medium, then placed outdoors over the winter. For those who like to tend their seed pots indoors, this species is one that will also germinate at room temperature without prechilling. Growth of the seedling is slow. Flowering can be expected in the spring of its second year and may continue into August.

Sources: Larry Davidson, member of ORG&HPS, carried the plant last season http://losthorizons.ca. Kristl Walek carried the seeds of this species last year at www.gardensnorth.com. She hasn't indicated whether it will be available this year.

Germination Tips:

Sow @ 20°C. Seed germinates within 3 months.

Requires light or the small seeds should be surface sown. See https://www.youtube.com/watch?v=RgkXUSI1GWo&index=1&list=UUJfYCNSWCIuOB2...

Clematis alpina header

Clematis alpina

(Klem –uh-tiss AL-pine-a)

General Information:

Clematis alpina is a very hardy, early flowering vine that adds a great splash of color in your spring garden and then goes on to make interesting seed heads in late summer. As seen in the picture below, I grow it in a planter, in zone 5 and leave it outside all year. You can also plant it in the garden and just about forget about it. It doesn't need to be pruned, and it will not take over most trees and shrubs the way some larger clematis do.

Clematis alpina main

Clematis alpina:photo by Robert Pavlis

Its main color is a blue/mauve but a variety called C. alpine var. sibirica (Siberian clematis) is white. If these colors are not to your liking cultivars of Clematis alpina are available in a variety of other colors including pinks and pale blues.

It is a Group 1 clematis so pruning should be done after it flowers in spring. If you want a taller plant, don’t prune it for a few years. After that, prune just for shape or size. In my planter I cut it to soil level after flowering so that it never gets taller than 3 to 4 feet.

C. alpina can be grown from seed fairly easily, but it does take some time. For more information on this see Growing Clematis From Seed.

Clematis alpina in bud

Clematis alpina:photo by Robert Pavlis

This clematis is not prone to clematis wilt, but it is still a good idea to plant it a few inches lower than in the original pot.

Alpine clematis is a close relative of anemone and hepatica which have similar leaves and flowers. It belongs to the Atragene Group which also includes species such as C. chiisanensis, C. fauriei, C. koreana, C. macropetala, C. ochotensis, C. sibirica, C. turkestanica.

Clematis alpina closeup

Clematis alpina:photo by Robert Pavlis

Life Cycle: woody vine

Height: 3 m (10 ft)

Bloom Time: spring

Natural Range: European Alps

Habitat: rocky and wooded sub-alpine areas

Synonyms: Atragene alpine

Cultivation:

Light: full sun to part shade, especially in warmer climates

Soil: well drained, humusy

Water: drought tolerant once established

USDA Hardiness Zone: 3 - 9

Propagation: seed, layering, softwood or semi-hardwood cuttings

Seedex availability (ORG&HPS annual Seed Exchange): usually

Germination Tips:

Use repeated cycles of 20°C, then 4°C for 3 months each. Germination is very prolonged.

Photos:

Contributions to this page were made by: Robert Pavlis

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