Jim Shields' Garden Notes
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Blog Home : October 2006

- Autumn Begins

We were in South Africa for most of September. See the South Africa 2006 Blog for notes.

When we returned, we found the flowers of summer were gone. In their place, the Colchicum were in full bloom! A few Sternbergia lutea were also in flower, and one lone scape of Crinum variabile was still in bloom. The hardy Hymenocallis occidentalis, that were just starting to bloom when we left, now had a few almost-ripe seeds instead.

In place of flowers, this season offers nuts. The black walnuts are all on the ground, waiting for someone to remove the husks. The English walnuts have long since disappeared, having been found by the squirrels as fast as they dropped.

A shelbark hickory tree dropped a few nuts, which my granddaughter must have found since they were lying on the front steps. Shelbarks are like hardy pecans, but the shells are as hard as a black walnut's. It takes special nutcrackers to crack these, if you want to recover any useful nutmeats from them.

The prize nuts, to me at least, are the Chinese Chestnuts. They are just hitting their stride now, leaving fresh crops on the ground every morning. There are too many of them for the even squirrels to take them all. There are too many of them for us to eat ourselves, too. Since some are wormy, and you can't always detect this before you cook them, we are reluctant to give them away.

Chestnuts, whether Chinese or Italian, can be roasted or boiled. We score the shells first, making an "X" that cuts through the tough skin, so they won't explode when we heat them. Boiled and peeled, they can be frozen for use long after the fresh chestnut season has ended. I prefer them roasted and eaten fresh and hot!

- Bulbs in Pots

We are still moving pots into winter storage, either the heated shed or one of the greenhouses. Lifting so many pots -- and even just watching people 50 years younger than I am lift them -- brings home how much potting mix we drag around here in the course of a year. Some of those pots are 7.5 gal. in (nominal) size, and many are "5 gal." size. Is there any reason for so much potting mix?

According to Dr. Dave Lehmiller, the resident expert on Crinum for the International Bulb Society, it is important to grow Crinum in very large pots. Writing in HERBERTIA, he has recommended using pots that are up to 24 inches deep and wide. Using smaller pots, you get a bonsai effect that does not represent the way the plant grows in nature. In the wild, the bulbs grow deep in the ground and have a large, very extensive root mass.

In a discussion recently in the on-line group of the Pacific Bulb Society, Alberto Castillo of Argentina discussed the effects of growing bulbs in pots rather than in the ground. He has stated unequivocally that if you can't grow them directly in the ground, you should at least grow them in very large pots. Alberto has said the he grows even his rain lilies (Zephyranthes and Habranthus, with very small bulbs) in 5-gal. size containers.

My theory for why so many garden books recommend growing bulbs root-bound in small pots has been that the average gardener can't resist over-watering potted plants. Others contest this, suggesting instead that bulbs with perennial roots resent being disturbed but bloom better with more massive root systems, and hence the advice so often given.

Perhaps the extreme case of the irrational advice to under-pot is Clivia. In nature, Clivia grow on the ground, on rocks, on fallen tree trunks, and even in crotches of standing trees. They have extensive root systems which are well-exposed to air. Even the plants growing on the ground have their roots mostly running on the surface of the clay soil, covered by the duff of fallen leaves. In a pot, even in a very large pot, over the years a Clivia plant will literally fill the pot with its roots. It seems a great mistake to try to grow Clivia root-bound in a small pot. If your Clivia eventually becomes root-bound in a 5-gal. container, then you can reasonably leave it root-bound. Otherwise, pot it up into the next-larger size pot once it has mostly filled its current pot with its roots.

- Unlikely Hardy Bulbs

One of my main interests is finding unlikely bulbs that can be grown outdoors here in central Indiana, USDA cold zone 5. It is not too late to plant hardy bulbs. Good ones to plant now are true lilies (Lilium) and the tulips (Tulipa). Of course, you can also plant Crocus, Narcissus, Hyacinthus, and all the traditional hardy bulbs up until the ground starts to freeze.

At one point, I thought Colchicum were unlikely candidates for hardy here, but that was merely a problem of ignorance on my part. It is now too late (October) for these bulbs, since they will have already bloomed. It is best to plant Colchicum in July or early August. Make a note to try a few next year.

I've tried several types of Fritillaria here, and most have not done well for me. The California frits have dwindled away. Most of the Chinese frits never came up. Fritillaria persica bulbs have come up for a year or two, but they don't bloom. Fritillaria imperialis bulbs have never ever come up even once; maybe I should plant them in the early spring instead of in the autumn.

Some Fritillaria do grow here. F. meleagris has come up in shaded areas for years, but naturalized in the grass it does not last more than a few seasons. Some F. camschatcensis from a few sources have survived and even flowered; I recommend Mr. Janis Ruksans Bulb Nursery in Latvia for these bulbs. F. crassifolia and F. acmopetala survive, flower, and set seeds. I can recommend these two species very highly to anyone gardening in a climate similar to mine. F. crassifolia is a dwarf species that I grow i full sun in my raised rock garden. F. acmopetala is about a foot tall and grows in one of the borders where it gets some afternoon shade and is in a clay soil. Both come easily from seed.

Sternbergia lutea seem to be doing well here in some spots. Out in the open in clay soil, they tend not to flower. Planted in a raised, sandy bed or under trees, they have flowered well for me and are probably increasing too; I just have not tried digging into the clump to see how many bulbs are there now. For a bright yellow spot in the late autumn garden, they are worth trying. They may look like Crocus, but Sternbergia are not related to Crocus at all. While Crocus are in the Iris Family, Sternbergia are in the Amaryllis Family.

Hardy Gladiolus come in two flavors. The spring flowering sorts, such as Gladiolus byzantinus, G. italicus, and G. imbricatus, all have pink-purple folowers and are native to Europe and the Caucusus regions.

The late-summer flowering Gladiolus are originally from South Africa. Most are treated as tender bulbs to be lifter at frost each autumn and replanted outdoors again in spring. However, some of them are fairly hardy here. I've found a couple species that seem to be hardy here: Gladiolus oppositiflorus salmoneus (salmon pink flowers) and G. gandavensis (primrose yellow flowers).

Probably the most surprising finding was that some Crinum are pretty hardy here too. Crinum x-powellii is usually suggested as the most cold-hardy type, with one of its parental species, Crinum bulbispermum being considered a close second in hardiness. Most Crinum are indeed tender to frost, and hence are well known only in the Old South. There, the hybrid known as Milk and Wine Lily is often found in old gardens.

Crinum variabile (c) copyright 2003 by Shields Gardens Ltd.  All rights reserved. We have found that the most hardy of these is Crinum variabile. It is a medium size plant that blooms, in Indiana, in August and September. This species is native to the Western Cape province of South Africa, a Mediterranean climate zone with winter rainfall. In its habitat, C. variabile grows in winter, when there is rain. In Indiana, it is dormant in the cold winter weather but starts growing again in spring.

For more information about Crinum: See more information on this topic

- Haemanthus Hybrids

The only hybrid in the genus Haemanthus that I knew of for years was one sold (erroneously) as "King Albert", a hybrid of [albiflos X coccineus]. It produces numerous offsets, hence it's occasional availablility commercially. It can also produce huge leaves, once measuring about 8 inches wide by about 16 inches long in my greenhouse. It has also bloomed for me once or twice. The umbel is smaller than those of either albiflos or coccineus, and is an off-color white, perhaps pale cream or pink. The inflorescence is not impressive.

In 2002, bulbs of both Haemanthus humilis hirsutus and H. coccineus bloomed for me at the same time, roughly late September or early October. I cross pollinated the two plants, and from the hirsutus I obtained 11 seeds in November. The seeds were cleaned and each was planted in a 5½ inches square by 5½ inches deep plastic pot in my Promix BX + sand (2 : 1) seed starting mix.

Haemanthus humilis hirsutus


This is the only plant of H. humilis hirsutus that I have seen bloom. The flowers are snow-white. It is the seed parent (female) of my [hirsutus X coccineus] hybrids. For a close up of the leaf and stalk, click the image at left.


The seedlings that resulted have narrow, deep wine-red margins on their leaves. Some have smooth leaves, others have hairy leaves. Although not all my H. coccineus plants have leaves with red margins, the pollen-parent of these hybrids does have the red margin. None of the plants of H. h. hirsutus that I grow have any sort of colored margin on their leaves.

Haemanthus hybrid (c) copyright 2006 by Shields Gardens Ltd.  All rights reserved. Haemanthus hybrid (c) copyright 2006 by Shields Gardens Ltd.  All rights reserved.

Now one of the bulbs is about to bloom. At least, it is sending up a bud. The bracts enclosing the inflorescence have been a rich burgundy red so far, similar to the color of the narrow red line on the margins of the leaves.

Haemanthus hybrid (c) copyright 2006 by Shields Gardens Ltd.  All rights reserved.


These are all winter-growing plants, dormant and leafless all summer long. They survive the summer under a bench in the greenhouse, even though the temperatures can reach 120°F (ca. 49°C) at that time.

I also made the cross H. [albiflos X humilis hirsutus] at the same time in autumn, 2002. I have two seedlings from that cross, which are mainly summer growing, but almost evergreen. It remains to be seen whether they are really the hybrid or just plain albiflos.

- Fall, Frost, and Greenhouses

Yesterday morning, we had a real frost: it dropped to 24°F for the first time since last spring. There was heavy frost on the roofs and on the ground in open areas. There was no wind at all; but when the sun came up, the leaves started drifting off the trees like huge, colorful snowflakes. Today it's raining, and it looks as if it will rain for a couple days. More leaves are going to fall, and our Fall color will diminish steadily from here on.

Fortunately, everything that we wanted to go into the greenhouses for the winter was already inside. Which reminds me that no greenhouse was ever big enough a year after it was built, no matter how big you made it. We store dormant tender plants in the dark inside our insulated, heated equipment storage shed. The gas furnace keeps the building at about 50°F all winter. Rain and snow coming in under the big overhead doors help keep the humidity up.

Alongside the tractor, the lawn mowers, the tillers, and the like, we have wide shelves filled with pots large and small. The top shelf has the most space overhead, so that is where our 5-gallon and 7.5-gallon pots of large Crinums are put. Smaller pots go lower down. When I can't find some lad 50 years younger than I am to move the pots into storage, I slide them into the front-loader of the Kubota and lift them to the shelves that way.

Pots of plants that, though dormant, need to have sunlight through winter go into the small hoop house just behind the equipment shed. This year, those are mainly Crinum seedlings in ½-gal. to 1-gal. containers.

Plants that will need a bit of water as well as a little light through winter go under the benches in the other greenhouses. These include the nearly-evergreen Hymenocallis species like acutifolia and liriosme ("Spider Lilies"). We also put the summer growing Nerine pots here too, even though they neither need nor get any water in winter. They do need to get a good chilling, and the floor of one of the glass-covered home greenhouses gets pretty chilly in mid-winter.

I never know where to put the pots of Zantedeschia ("Calla Lilies") over winter. Some are sitting on the concrete floor of the big clivia greenhouse; some are under benches in the smaller greenhouses. Mostly they make it through winter in good shape and grow again once moved outdoors the next summer. The Zantedeschia aethiopica would probably like to stay evergreen; but I don't bother watering them in winter, and they eventually lose their green leaves. My seedlings of Strelitzia reginae ("Bird of Paradise" or "Crane Flower") probably want to be evergreen too, but the long, dark winter days eventually force them to shed their foliage.

Irma, my wife, grows ivy-leaf or hanging geraniums (vining Pelargonium hybrids) in hanging baskets outdoors around our house in summer. For the winter, I hang them in the small glass home greenhouses. Hanging geraniums do not tolerate winter storage bone dry or in the dark. They need sunlight and occasional watering all winter long, but they also continue flowering through most of the winter. This gives some otherwise pretty drab greenhouses a splash of color through the dreary winter months. It's a good deal for both of us: Irma can carry her hanging geraniums over the winter, and I get some needed color in the greenhouses.

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Last revised on: 11 November 2006
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