Hands-on Growing Experiences

• Primula I Have Grown
  • Written by Karen Schellinger and edited by Chuck Carlson
• Complaints of an Alpine
  • By Shirley Friberg
• Buns, The Cushions of the Rock Garden
  • By Shirley Friberg

Primula I Have Grown

Written by Karen Schellinger and edited by Chuck Carlson

[Members of the NARGS Minnesota Chapter]

In general I grow my own plants from seeds I buy or get from the seed exchange.
When sowing seeds, carefully sprinkle the primula seeds on top of the moist pro mix. As primula seed needs light to germinate, I will LIGHTLY sprinkle moist pro mix over them so they are barely covered. This procedure is for inside my greenhouse. For flats and pots of seeds that go outside and subjected to rain and wind after germination, I sprinkle #1 and #2 granite chick grit sparsely over the seed. It protects the seeds from the occasional downpour of rain or spray from the watering hose. The seeds should be exposed to temperatures no higher than 65-70 degrees when in the greenhouse. Higher temperatures will force the seed into dormancy. The ideal thing for germinating, if you are in no hurry, is to place them outside until April when they start to germinate. You may bring the flats into the greenhouse the end of March if you like to get a jump on the germination as it will take from 3-4 weeks to germinate. You must keep them out of direct sunlight and keep them moist. If the germinating seeds dry out, it will kill them.

Those started last November in the cool greenhouse are healthy seedlings ready for transplanting in mid-April. It is fun to see their crinkled green leaves so healthy and just begging for a little larger root room. I put them into deep 2" pots and put them outside in the woodland after we are assured of no hard frosts. Here they get plenty of filtered shade under the early spring tree canopy. In April I also check every day to see if any of the older primroses were awakening from their winter slumber and finally I began to see signs that the primroses had indeed made it through our Minnesota winter. These were all started in the little green house last year. The new plants are then planted out into the garden in June or July if they have four leaves. Primroses like, even, moist, very organic conditions created by digging in 6 inches of peat or good compost in the planting area. Primroses take a few years to become large stunning blooming plants. By their 3rd year they are at their best and from then on it is best to divide them every 4th year or at the end of their blooming in their 3rd year.

The following are primroses I have had success with in Minnesota. Remember that some primroses like other perennials are short-lived, while some, given the right growing conditions, will last for quite some time.

Primula acaulis has for me been rather short lived but I like to grow them anyway which gives a selection of colors with one bloom per single stem. The growth habit of this plant makes a low mound of color.

Primula denticulata has lilac, pink or white balls of bloom on 6-8 inch stalks the first thing in the spring. They need a good amount of moisture to do well and survive. The leaves are rather long and coarse but their flowers are well worth it. They must be well drained in winter. They are long lived with proper division.

Primula Juliana; Wanda and other hybrids of Primula juliae are worth growing for their compact growth and floriferous display in early spring. Some are more hairy than others in this group.

Primula veris as a species is a more natural looking; fragrant plant with bright yellow drooping bells on stalks 6-8 inches tall. A very tough primula, which will take more light than most, if given enough water, though it gets by with less moisture than most primula.. You can't just forget about them, however!

Primula polyanthus is an 8-inch stalked hybrid between the wild Primula veris, elatior and the primrose. There are many beautiful colors among this primula but I have only had luck with the Barnhaven seed strain. One very beautiful primula is Primula gold laced. The petals are quite dark red or black and the tips of each petal are edged in white or gold. They are one of my favorites. I was lucky enough to get the silver laced form only once and then after a few years lost it. The gold laced is more common among the seeds offered for sale. Another member of the group of Primula polyanthus are referred to as the traditional mix, one among that group is called hose-in-hose, which is one flower inside of another bloom. They are quite charming and come in several colors.

Primula elatior, another species, is one of my favorite early spring bloomers. It does not hang its yellow flowers quite so much and has proven to be quite hardy for me in my garden and one of the first ones I started from seed and planted out when big enough and it is still with me.

Primula farinosa is a dainty pink-flowered plant 3 inches in height. It likes a gritty, moist. The correct conditions in the garden and when happy will reseed. It also will benefit from dividing, as it tends to pop out of the ground a bit after the winter months. Check them throughout the summer as well since repeated watering can expose the crown.

Primula frondosa is a slightly coarser plant with pink flowers and a bit taller but still a smaller primose that likes a gritty, moist area.

Primula auricula has leathery leaves and very fragrant flowers. It is 6 inches tall and likes gritty compost made up of limestone chips and compost. They also need to be divided when the plant has become too large and the flowering has dwindled. The flower colors are blue, yellow, red, pink and white.

Species alpine primula are smaller versions of the auricula. These will be more fussy than the auricula but are more in character with the wild mountain plants that grow among them. The species or the auricula do not like hot sun so tuck them behind a rock on the shady side or in a bed that has sun until 10 a.m.Place small rock mulch around them. Use either the small limestone mulch or pea gravel. Both work well, although the limestone may be preferred. I wonder if we are choosing things for our plants rather than the plants really preferring it.

Primula marginata is a plant whose seed I have not had much luck in germinating. Perhaps I got seed that was too old. But you can buy plants from nurseries. They are wonderful plants with a totally different type of foliage - toothed edges with a powdery white farina on their leaves. They also like gritty soil and no exposure to hot sun, with a small stone mulch.

Woodland primulas as a group love the rich soil. If not available in your woodland area, work some organic additives into it. I don't think you can add too much rich organic matter for woodland primulas.

Primula sieboldii is the best known of this group of primula. They are 8 inches tall and have wonderful flowers with notched lacy petals in colors of pink, dark pink, lavender and white and will multiply from rhizomes over the years. The seed will germinate when placed outside if the seed is not too old. This may take patience and not all will germinate at the same time. It was really a surprise in their first year after planting sieboldii it bloomed. It should put on an even better show the second year. Primula sieboldii does go dormant towards the end of the summer if they don't get enough water. It doesn't hurt them however as they're back again the following spring. If well watered, they will keep growing right into October.

Primula saxatilis is a lovely primula with pink flowers and 8 inches tall with leaves similar to Primula sieboldii, but they do not spread by rhizomes but from the crown.

Primula cortusoides is similar to saxatilis but will sometimes grow two tiers of flower clusters. Both germinate easily.

Primula kisoana is 6-8 inches tall and pink-flowered with broad hairy leaves and will make a groundcover in the woodland. It is sometimes available in a white flowered form also. It is noted for its ease of cultivation.

Primula polyneura is pink flowered on 8-inch stems and is one of my favorites with nicely textured leaves coming from a crown. It reminds me of Primula kisoana except it does not run like kisoana and it is not as long lived.

The next two are the candelabra bog group of primula and need very wet, even stream-side, conditions. I have tried them in the past and was not successful until I placed them where my irrigation system watered them in the heavy, moist soil close to the sprinkler head.

Primula japonica is the hardiest and its seed germinates like grass. All these primula are larger plants (12+ inches) and have white or pink flowers in 2 or 3 clusters. They bloom later than the spring primula

Primula pulverulenta has silver stems with rich warm pink and it has some hybrids called Bartley strain in seed lists.

There are others in the candelabra group but I haven’t tried them.

To end this primula discussion here are the top six reasons for primula failure in Zones 3 or 4 and in general it may be good for other zones also.

1. Not enough water throughout the growing season.
2. Not dividing plants at least every 3rd or 4th year after the bloom period.
3. Planting the crowns too high when planting
4. Not giving enough cover for the winter months in the form of leaves or straw. Also evergreen branches can be laid the bed. The branches will catch even more leaves when the winds blow. An early snow would be wonderful also. No snow cover is deadly for primroses in Zones 3 or 4.
5. Do not plant seedlings in October. Mulching will not protect them. It is really too late to be planting seedlings in October in Minnesota’s Zones 3 or 4.
6. Planting or dividing and then not watering them enough. When they are limp, sad little piles of leaves, it may be too late! Be generous with the water during the warm summer days.

Complaints of an Alpine

By Shirley Friberg

[Member of the Minnesota Chapter of NARGS]

This could have been titled The Revelation of Saxifraga 'Toyo Yatsabusa'.

"You certainly expect a lot of me. First I am drenched with water in May, then there was only a sprinkling of rain, next came 10 days of 90+ degrees and scorching sun with high humidity, and what do you do but cut down the only tree that gave me shade.

"Now I am not just complaining alone, many of my neighbors have also felt the results and are quite ill, although not as sick as I. So if I die, you really can't blame me.

"You have to remember that I, distant relatives, and friends (Saxifraga 'Winifred Bevington', Heuchera nevalis and Picea glauca 'Alberta Dwarf Globe') moved here from a much different climate. It was much cooler and without that unpleasant humidity. Of course we had a shorter season, but it never was hot, hot, hot.

"I know I have neighbors, Dianthus, Gypsophila and Draba that survived this scourge. They don't have the delicate nature that we have. They must be from the lower regions as they seem to be able to endure almost anything. I hope you will be kinder to me in the future."

Buns, The Cushions of the Rock Garden

By Shirley Friberg

[Member of the Minnesota Chapter of NARGS]

It was small "buns" that first sparked my interest in rock gardening. I had never seen plants so small and compact. Their ability to bloom and live outside in Minnesota winters was real incentive to grow them. Since building two rock gardens I have grown a variety of "buns." One of my oldest, Gypsophila aretoides, was planted in 1997. It is one of the tiniest plants. It is in the family of baby's breath. The thought that this tiny mound is related to the delicate, broad spreading 30" perennial is quite amazing. Cushion plants (the more accepted term for "buns") come from a wide variety of families with different leaf patterns, size and flowers. What is common to all is their round shape, which is small with very dense foliage. The mound, dome or "bun" shape can be distorted by external influences such as rocks or other plants. Plant hunters brought back the seed of many species. Some of these were hybridized for larger lowers or special plant features. The size and shape of cushion plants demonstrates how they have adapted to severe conditions. Where soil, sand, gravel and rock come together, cushion plants grow, surviving harsh weather conditions. The conditions that create cushion plants can be located above the tree line on mountains, in deserts, in cold or hot climates. Many cushion plants are Alpines, coming from above the tree line in mountainous regions. Some cushion plants are in the same family as our large perennials, such as the gypsophilia and dianthus.

Cushion plants ("buns") have tiny, tight foliage to reduce the amount of dehydration when exposed to a windy climate. Almost all cushion plants are perennial. Most grow from one long main root or a long spreading root. They grow slowly, forming a larger and larger "bun" shape. As they grow, the living stems retain their leaves but have a dense, dead core, giving the plant a” sturdy feel." Their long, penetrating root system assists them to hold fast in their location and burrow between rocks. To perpetuate the species, they bloom abundantly, producing much seed. Due to the harsh conditions, few seeds find suitable habitat to grow. In a very short season, 3-4 months, the plant must grow, bloom and produce seed. Most "buns" are evergreen. At the high elevations winter cold comes on quickly with no long period of rain or wet. The plants hibernate under deep layers of snow. Therefore, cushion plants do not tolerate long fall or winter seasons that are wet.

Our wet fall presents a problem. I save large, clear plastic bottles (pop), which are cut in half and placed over the plants. Clear plastic of any type, such as those on cakes or donuts, can also be used. They must be placed so that there is some airflow in other words, do not make the cover airtight. Soil for my small cushion plants is lean. Sand, chicken grit or Turface (baked clay particles) are added to the soil. I try to plant the buns on a slant for good drainage. They can be best appreciated in a trough or raised bed. Once frozen, they are covered with marsh hay, which I reuse each year. It is light, fluffy and dries out quickly.

The following are a list of plants I have successfully grown in Minnesota:

1. Asperula sintensii (Alpine Woodruff) -1/2"X5"; it has fragrant pink flowers on grey green mossy foliage.
2. Saxifraga paniculata 'Minutifolia' - 1/4"X2"; red colored on underside of tiny rosette leaves. It is growing in tufa rock.
3. Saxifraga paniculata 'Millstream' - 1"X6"; silver saxifrage with 1" rosettes and showy red flowers. It has dropped a rosette that has made a nice mound at the bottom of a tufa rock. Rapid grower.
4. Saxifraga apiculata (Kabschia) - 1/4"X6"; closely packed, cushioned rosettes with yellow flowers.
5. Saxifraga 'Jenkinsae' - 1/2"X2"; tiny, glaucous, grey-green rosettes with bluish pink flowers.
6. Saxifraga paniculata 'Foster Red' - 1"X4"; white edged, small tight green rosettes with red flowers.
7. Dianthus 'Mrs. Holt' - 1"X10"(eventually); neat blue foliage which slowly mounds. It has pink flowers on 3" stems.
8. Lewisia 'Pinkie' (L. longipetala x L.cotyledon) - 2"X4"; it forms a nice tight "bun" of quill-like leaves. Pink flowers. Easy to grow and divide.
9. Androsace primuloides 'Chumbyi' - 3"X6"; downy rosettes with lavender pink flowers like tiny primroses.
10. Arabis ferdinandi-coburgi 'Variegata' - 2"X6"; white and green striped leaves in overlapping rosettes. White flowers.
11. Gypsophila aretoides - 1"X3"; tiny pinhead rosettes form a mound that grows ever so slowly. Planted in 1997, shaded by a small Abies koreana 'Silberlocke', it was moved in 2003 to a south, sunny location.
12. Draba x salomonii - 1/2"X4"; bristly green rosettes, pincushion shaped with white flowers.
13. Dianthus erinaceus - 3"X4"; a tight, prickly green mound with pink flowers
14. Saxifraga primuloides 'Elliott's Variety'; 2"X6"; dainty rose pink flowers with dark green leathery leaves. Planted in 2003.
15. Saxifraga 'Winifred Bevington' - 1"X6"; bright green rosettes with white along the leaf borders. Blush pink flowers. Mine faces NE and is a 1"X2" ball.
16. Saxifraga paniculata 'Hi Ace' - 1/4"X6"; a tiny encrusted saxifrage with silver edged rosettes growing as a spreading mound in a crack of tufa rock. Planted in 2003.
17. Saxifraga 'Bob Hawkins' - 2"X6"; a mossy saxifrage with variegated light green and white cut fast growing foliage and pink flowers. Planted in 2004.

There are other Draba, Dianthus, Arabis plus other plants that grow in mounds.

Try some; you will be delighted to see these “buns” in your rock garden.

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