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- It's Been a Long Spring and Summer!

Garden Blog for May - September, 2009

I've been a long time getting back to the blog. In fact, it has been over 5 months. My apologies!

Trillium in the Smokies

In early April, I spent four days in Gatlinburg and the Great Smoky Mountains National Park area, looking at Trillium in bloom and collecting a few specimens for possible breeding work next year. For the record, I have a research permit for the Great Smoky Mountains National Park to study Trillium species there. The permit allows collection of a few plants for the study. Most of the plants I collected came from roadsides outside the park boundaries.

There are two species in the pedicellate group listed that seem to intergrade: Trillium erectum album, the white flowered form of a species that ranges from the Smokies along higher elevations in the Appalachian Mountains northward to Canada, where it spreads out over Quebec and Ontario. Then there is Trillium simile, also white flowered but localized in the lower elevations and limited to the area immediately around Gatlinburg, Tennessee, and eastward to the type locality near Tryon, North Carolina.

Susan Farmer in her publication based on her Ph.D. thesis at the University of Tennessee, finds that erectum and simile are not immediate neighbors in the molecular phylogenetic trees she calculated based on DNA sequences of a few genes. None the less, there appears to be a cline (a gradient) from simile around Gatlinburg at about 1200 ft. elevation, with intermediates up to pure erectum album at high elevations, the top being at Newfound Gap (elevation 5000 ft.) and Clingman's Dome (el. 6000 ft.).

The research project is devoted to studying the possibly intimate relationship between these two species.

Another interesting pair of species is T. luetum, with yellow flowers, and T. cunneatum, with red/brown flowers. The plants are both in the sessile group, both grow to be about the same size, look remarkably similar aside from the flower petals, and while the yellow luteum occasionally has a plant with brown petals, the brown cuneatum occasionally has a plant with yellow petals.

Again, Susan Farmer's article does not show them being particularly closely related to one another. And yet, populations of yellow luteum seem to be found occasionally inserted between populations of cuneatum. This is another pair of species whose DNA sequences could probably tell us a great deal.

Albino Flowers?

An interesting discussion erupted in the Spring in the Trillium-L list about the question, just what constitutes an albino flower in the Trillium?

I have my own set of definitions, and I reproduce some of my comments to that list herewith:

What I mean by "albino" is an individual plant or animal that has a mutation that blocks the biosynthesis of a particular class of pigment throughout the entire organism. This would be a mutation that inactivated the gene or gene product. Gene products that are enzymes are what I mean, enzymes that carry out one step in the formation of one product on the pathway to a pigment. Let's refer to genes that code for enzymes as "Structural Genes."

There are other kinds of genes as well -- regulatory genes that directly or indirectly control the synthesis or activity of structural genes or their gene products. Regulatory genes can code for proteins, for RNAs, or they may just be gene promoters, sequences that promote or inhibit the activation of another gene. Regulatory genes make up the differences in color pattern in multicolored flowers, e.g., in Dutch amaryllis like 'Apple Blossom'. The red purple ovary in Trillium erectum album is an example of regulatory genes at work, turning the red color (anthocyanin) biosynthesis pathway "ON" in the ovary and "OFF" in the petals.

If a plant has white flowers but has any pink, orange, or red anywhere else in the plant, it is not a "albino" by my definition.

Note that there are numerous ways to use the term "albino" in regard to plants. A seedling that is totally lacking in chlorophyll is termed an albino, but in this case in regard to the synthesis of functional chloroplasts that contain normal chlorophyll. In the absence of human intervention (e.g., putting the seedling into tissue culture) this is an eventually lethal mutation.

I think that a defect in the biosynthetic pathway for carotenes is probably also lethal in plants. The yellow color from carotenoids may be turned off in flower petals, but if the pathway itself is mutated and non-functional, the seedling with such a mutation probably dies quickly. So we can talk about carotene albinos but I don't think we can produce them.

So, where we are talking about flower colors and anthocyanin pigments, we can call it an "albino" if there is a Structural Gene mutation that prevents anthocyanin synthesis.

If we are talking about preventing anthocyanin synthesis in all or parts of the flowers, but not in other places -- stem, bracts (i.e., "leaves"), sepals, or fruit, we are dealing with operation of Regulatory Genes, and we cannot call those "albino."

Summer's End

The summer, especially July, was cooler than usual. There were many chilly nights. The result was that some Haemanthus started blooming in early August. In August, the Lycoris bloomed, pretty much on schedule. Now at the beginning of September, a few Colchicum flowers have started to appear.

This past month saw one of my bulbs of Haemanthus namaquensis bloom for the first time ever. In fact this is my first-ever bloom on Haemanthus namaquensis. This plant was grown from seed provided by Silverhill Seeds and planted here in 1997. The bulb is growing in a 9-in diameter by 9 inches deep pot in a very gritty mix. The inflorescence is about 7.5 inches tall, of which ca. 2.5 inches is the umbel. The leaves on this particular specimen do not have the wavy edges typical of most namaquensis.

Haemanthus namaquensis (c) copyright Shields Gardens Ltd.  All rights reserved.

The picture was taken on the peak day of the bloom, Aug. 31st. It's now starting to go over somewhat.

Good gardening,


- Outdoor Bloom Season Nearing its End

With the flowering of the Colchicum bulbs, the outdoor bloom season is about at its end for 2009.

Colchicum is a genus traditionally lumped into the Lily Family (Liliaceae), but that conglomeration of monocot flowers has been separated into two groups, the Order Asparagales with families like Asparagaceae (asparagus), Alliaceae (onions), Iridaceae (irises), Orchidaceae (orchids), and others, while the true lilies are in the Order Liliales with families like Liliaceae, Trilliaceae, Melanthiaceae, Colchicaceae, and others.

Other plants in the Colchicaceae besides Colchicum include Androcymbium and Gloriosa. I have a couple of species of Androcymbium in the greenhouse, but I've never grown Gloriosa. The Androcymbium may need more sunlight in winter than we get here. I also have a pot of Oxinotis triqueta.

Hymenocallis occidentalis (c) copyright 2009 by Shields Gardens Ltd.  All rights reserved. The hardy Hymenocallis occidentalis is also starting to bloom now. The petals span 8 inches, tip to tip.
Hymenocallis occidentalis.

Also in pots, we have blooms on Haemanthus albiflos. This is the commonest Haemanthus in cultivation, and is quite easy to grow in a pot. It would be a fine windowsill plant; leaves are evergreen; and it blooms in autumn. It is not terribly sensitive to moisture, and does not have a dormant period when it must be kept absolutely dry.

I had a bloom on Brunsvigia litoralis this summer. Brunsvigia litoralis (c) copyright 2009 by Shields Gardens Ltd.  All rights reserved. Native to the Southern and Eastern Cape area of South Africa, it is somewhat smaller than the largest members of this genus. This bulb is from seed I planted in 1999, so it took 10 years to reach bloom size! The bulb is currently growing in a 2-gal. pot (about 9 inches in diameter by 9 inches deep) in gritty mix. The individual florets opened one at a time over a period of a couple weeks.
Brunsvigia litoralis.

Scadoxus membranaceus (c) copyright 2009 by Shields Gardens Ltd.  All rights reserved. Also blooming now is one pot of Scadoxus membranaceus. I find this one very hard to get to flower, and this is only the second time I've had one of these to bloom.
Scadoxus membranaceus

Lycoris caldwellii (c) copyright 2009 by Shields Gardens Ltd.  All rights reserved. The last Lycoris blooming are L. caldwellii, a very hard sterile triploid that should grow anywhere that Lycoris squamigera grows well.
Lycoris caldwellii

An interesting new on-line plant forum is Xeric World at http://www.xericworld.com/forums/featured-discussion-forums/. Take a look at it sometime. Discussion topic include Aloaceae, Cactaceae, Geophytes, and Palms among others. The Amaryllidaceae are in the Geophytes section.

Good gardening,


- Positive Side of Autumn Coming

I find several positive aspects to autumn coming: The Colchicum start to bloom; the Chinese chestnuts will soon ripen; several of the Nerine species bloom; and this time at least, some Cyrtanthus are blooming!

Colchicum cilicicum 'Purpureum' is blooming in one of the beds. This year it is the first to flower.

Colchicum cilicicum 'Purpureum' (c) copyright 2009 by Shields Gardens Ltd.  All rights reserved. The substance colchicine is isolated from plants in the genus Colchicum. Colchicine is used by plant scientists to induce chromosome doubling. It does this by interfering with the function of tubulin inside the cell. At one time it was used to treat gout, but it is generally considered too dangerous to use in human medicine now.
Colchicum cilicicum 'Purpureum'
© 2009 by Shields Gardens Ltd.
All rights reserved.

Colchicum 'The Giant' has also started to bloom, followed by C. byzantinum. We also have a large group of Colchicum speciosum naturalized in the front lawn.

The genus Colchicum is native to the Mediterranean region and extends west as far as Great Britain and east to Iran and Turkistan. Many of the species are hardy in USDA zone 5.

Among the potted plants, Cyrtanthus montanus, C. sanguineus, and C. [elatus x montanus] have been blooming. These varieties have full, flaring flowers.

Cyrtanthus sanguineus (c) copyright 2009 by Shields Gardens Ltd.  All rights reserved. This species has only a single flower per scape, and in my greenhouse it flowers only occasionally. I was luck to get two blooms at one with this 6-inch pot.
Cyrtanthus sanguineus
© 2009 by Shields Gardens Ltd.
All rights reserved.

Cyrtanthus montanus has large erect flared flowers but they differ from sanguineus in having multiple flowers in the umbel and the tepal segments (petals and sepals) are narrower.

Cyrtanthus montanus (c) copyright 2009 by Shields Gardens Ltd.  All rights reserved. My attempt to cross sanguineus with montanus pollen did not yield a seed pod. C. montanus itself occasionally produces a small seed pod, but I have not checked the spontaneous seeds for viability. Even C. [elatus x montanus] sometimes produces a seed pod.
Cyrtanthus montanus
© 2009 by Shields Gardens Ltd.
All rights reserved.

Nerine [filifolia x krigei] is a hybrid that I made some years back. The plants seem to be completely sterile, and they are intermediate between the two parent species. I had hopped for some enhanced hardiness -- the filifloia plants supposedly originated near the crest of the Drakensberg Escarpement.

Nerine [filamentosa x krigei] (c) copyright 2009 by Shields Gardens Ltd.  All rights reserved. These flowers are blooming late this year, perhaps because I was slow getting them out of the greenhouse and watering them in early summer. The individual blooms are about 2 inches across.
Nerine [filifolia x krigei]
© 2009 by Shields Gardens Ltd.
All rights reserved.

Nerine masoniorum is blooming for me for the first time this year. I have the clump in a 2-gal. pot now. Always before, I grew them in a 6-inch azalea pot (only 4 or 5 inches deep).

Nerine masoniorum (c) copyright 2009 by Shields Gardens Ltd.  All rights reserved.

These flowers are tiny -- only 3/4 inch across.
Nerine masoniorum
© 2009 by Shields Gardens Ltd.
All rights reserved.

Finally, Nerine platypetala is in bloom. Thus species normally occurs in seasonal marshes where it blooms in standing water. In the past I have grown it in pots sitting in a tray of water all summer long.

Nerine platypetala (c) copyright 2009 by Shields Gardens Ltd.  All rights reserved. This flower is 1¼ inch across. The peduncle (stem) is 12 to 15 inches tall.
Nerine platypetala
© 2009 by Shields Gardens Ltd.
All rights reserved.

These Nerine species and hybrids are all summer growing plants that are kept bone dry in winter. They sit in their pots on the floor under benches in the greenhouses during the cold weather. They are very easy to grow, since they don't need any care at all in winter.

Good gardening,


- Time to Repot Winter-growing Plants

I'm in the middle of repotting my winter-growing bulbs. Plants grown in containers usually do better if they are repotted every few years. If they are already as big as you want them to mget, put them back into the same size container, even back into the same one you took them out of. Just replace as much of the potting mix as you can without damaging the roots.

They should be replanted just as they are starting to come out of dormancy but before they have a lot of new, tender leaves. This way, they continue growing without suffering a big setback from shock. In fact, I remove very little of the old potting mix. In my case, almost all my repotting is to put the bulbs into larger pots. I want them to get bigger, as many plants cannpt flower until they have built up a certain minimum mass of healthy tissue. They may need to have plenty of carbohydrates stored up to provide the energy needed to manufacture a flower.

To get many bulbs to grow to a big enough size to bloom, you will have to work them up till they are growing in very large containers. David Lehmiller grows his Crinum in 24-inch diameter pots. I have some Crinum growing in 7-gal. pots, but I can't move any pots larger than that so 7-gallon size is my limit. My Zantedeschia aethiopica are moving toward 3-gal. pots and a couple are in 5-gal. pots. I am working my Haemanthus bulbs gradually into individual 2-gallon (9-inch) pots.

Lots of these plants need extensive roots systems as well as big, fat, healthy bulbs. Clivia plants have only their root systems. Growing bulbs in larger pots will get large root systems on your plants faster than crowding them into small pots can ever accomplish.

The corollary to this for summer growing plants is to divide and repot them in spring, just as they are starting to grow again.

When you don't know anything specific to contradict these rules, follow them! A specific exception is Trillium. Experts have found that Trillium survive transplanting and dividing better when it is done immediately after they finish blooming. Trillium produce new roots and new growth eyes on the rhizomes in summer, so the start of summer is the best time to divide them.

Another exception would be Colchicum and Lycoris (at least in colder climates). Dig the bulbs as soon as the leaves die down in mid-summer and replant immediatgely. Don't allow the roots of Lycoris to dry out and die; the Colchicum probably wopn't have any roots.

Good gardening,


- Some Cacti Are Tough

Hardy Cacti and Succulents

We have several hardy cacti growing here. Opuntia humifusa is native to the Midwest, including Indiana. I have some O. humifusa ex hort, from the Indianapolis Zoo. Opuntia phaeacantha is hardy in Colorado, and I have some of this species collected in the wild southeast of Denver. These are very tough cacti. They can even survive a year on top of a fencepost.

A number of others have survived at least one winter outdoors in a sheltered bed. This bed is raised about 6 inches to a foot, filled with gravel, sand, and pea gravel. These include Echinocereus, Escobaria, Pediocactus, and Opuntia:

Echinocereus coccineus
Echinocereus reichenbachii caespitosus
Echinocereus viridiflorus
Escobaria sanbergii
Escobaria sneedii
Escobaria vivipara bisbeana
Pediocactus simpsonii
Opuntia arenaria
Opuntia fragilis
Opuntia imbricate
Opuntia polyacantha 'Crystal Tide'
Opuntia viridiflora
Opuntia whipplei

Pediocactus simpsonii (c) 2009 by Shields Gardens Ltd.  All rights reserved.         Opuntia phaeacantha (c) 2009 by Shields Gardens Ltd.  All rights reserved.
Pediocactus simpsonii (left) and Opuntia phaeacantha (right). The diameter of the entire Pediocactus plant is smaller than the diameter of the flower on the opuntia.

Yucca filamentosa is of course also hardy here. Visit almost any old cemetery and you'll find Yucca growing there.

Succulents like Sempervivum are on my list. I am interested in trying Agave parryi here for its hardiness as well. I'm not sure what else I might try for hardiness, but I'm open to suggestions.

Time to Refresh your Markers

This is a good time to replace old, faded, and broken markers with new ones. By next Spring, you won't be able to find or read the markers that are marginal this Fall. Do it now!

I am partial to metal markers and I use a Brother PT-2700 label maker for the labels. The TZ line of label tapes have a UV-resistant clear lamination layer which greatly improves the lasting power of these labels outdoors. Highly recommended!

Plastic markers come out of the ground over winter and blow away. You could switch to metal markers, or you could make duplicate plastic markers for each plant and bury one under the soil or under a rock.

Good gardening,


- Some Cacti Sources; Fall is Here

Sources of Hardy Cacti and Succulents

Here are some places that have been recommended to me as sources of cold hardy cacti and succulents. I have not done business with all of these firms, so please let me know your experiences with them. Send comments to <blog@shieldsgardens.com>

  • Cold Hardy Cactus http://www.coldhardycactus.com/index.htm
  • High Country Gardens http://www.highcountrygardens.com/
  • Mesa Garden http://www.mesagarden.com/index.html
  • Plant Delights http://www.plantdelights.com/

From what I am reading, winter cold is not so dangerous as winter wet, especially wet snow. The plants I already have growing have done fine here, but if I get some hardy Agave, it appears that I may need to cover them in winter with buckets or a low poly tunnel.

Chestnuts Ripening

The first tree of Chinese Chestnuts has suddenly started dropping ripe nuts, almost overnight. The nuts on this tree are always smaller than the other two trees' nuts, but the dry summer we are having seems to have made all the nuts smaller than usual.

We have six Chinese Chestnut trees. Three were free or cheap from the National Arbor Day Foundation (it was almost 30 years ago, so that name may not be correct) and the other three I bought, probably from Miller Nursery (mail order fruit trees, etc.) The first three have very small nuts with poor flavor; even the squirrels will not eat them. The three trees from Miller have excellent nuts, sometimes fully as good as the Italian chestnuts we can buy in the fancier food markets. The squirrels love them!

Twenty years ago, I bought a couple seedlings of the hybrid Chinese x American chestnuts trees. Both died within a year of planting. I decided not to try again. It took at least ten years for our Chinese chestnut trees to bear their very first nuts, if I recall correctly. I don't have time to wait for new trees to grow to bearing size.

Chinese Chestnut (c) copyright 2009 by Shields Gardens Ltd.  All rights reserved. Chinese chestnut trees are multi-trunk trees of medium size. The leaves are simple with toothed edges. The fruits are a large spiny burr containing one to three nuts. The burrs split open when the nuts are ripe, allowing them to fall to the ground. The nuts shown are about 1.37 inches wide (35 mm.). The leaves are single; this image shows a twig with 7 individual leaves on it.

Chestnuts, including Chinese Chestnuts, are very good to eat. They can be roasted or boiled. In either case, cut through the tough outer skin before heating. Freshly roasted chestnuts are best eaten from the hand on a frosty autumn day, when they go very nicely with a big glass of fresh apple cider. Boiled and peeled chestnuts can be added to sauerkraut, red cabbage, and turkey dressing. Vermicelli made from roasted or boiled chestnuts is good as a dessert, and it's even better topped with whipped cream.

Good gardening,


- UC Berkeley Botanical Garden Does Mail Order Now

Plants from Berkeley

I recently received an order of plants for the University of California Botaincal Garden at Berkeley. The prices are reasonable, the shipping was fine, and the plants were things I had wanted for a while -- a few Aloe, a couple Agave, a few Arisaema, and two small bulbs of Brunsvigia species. I'm really delighted that the UC Botanical Garden is starting to do mail order sales now.

Check them out at Berkeley Plant Sale and at http://ucbglcs.blogspot.com/. The home page for the garden is at http://botanicalgarden.berkeley.edu.

An Inquiry

A gentleman in Oregon wrote to ask about Haemanthus humilis, "I have one of these large leaf forms for the past 3 years. It has not flowered but probably is mature enough to flower. I live in Portland, Oregon and have kept it outside in shade during the summer and put in indoors in the winter. It just started to put out new leaves. How low a temperature can these take in a pot?"

My reply: Here in Indiana, I am just putting my humilis humilis (pink) and humilis hirsutus (white) into the greenhouse for the winter. They can take a light frost for a short period of time, but I would not risk them in my zone 5 climate after about October 10th.

Both varieties are kept bone dry over winter in a cool but frost free greenhouse. Once a bulb of humilis humilis gets large enough to bloom, that bulb will then bloom almost every year. In the case of h. hirsutus, the mature bulbs seem to bloom rarely if at all for me. My humilis humilis bloom in early July and leaf out right after blooming. My h. hirsutus bloom in late July and leaf out a couple weeks after that. Two of my hirsutus bloomed this summer, for the first time in probably about 8 or 10 years.

He wrote further, "You mention that you keep them dry during the winter. Should I expect to see leaf dieback as we move into the winter months? In the past, I never really saw what I would call a dormant period perhaps because I kept them in my living room which is too warm to promote dormancy. If the leaves do die off I could move into my garage for the winter. It drops to around 40 degrees and never below."

I would suggest that he let them stay green for at least 3 or 4 month. After that, dry them off completely and do move them to the cool garage. I don't know that Haemanthus humilis requires an enforced dormancy to trigger flowering; but I suspect so, as it is true of most plants in the Amaryllis Family. Haemanthus are of course in the Amaryllis Family.

Burgundy Haemanthus

One of my seedling bulbs of Haemanthus [humilis hirsutus x coccineus] -- all of which bloom with burgundy bracts surrounding scarlet flowers -- is putting up twin scapes this year. This bulb first bloomed in 2007; it was in fact the very first from this cross to bloom for me.

Haemanthus [humilis hirsutus x coccineus] No. 1534.A (c) copyright 2009 by Shields Gardens Ltd.  All rights reserved. I hope this means it is going to divide. The seed parent (hirsutus) does make offsets, while the pollen parent, coccineus, does not seem to ever offset.
Haemanthus [humilis hirsutus x coccineus]
No. 1534.A

Good gardening,


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