In This Issue:

Beneath the Soil by Michael Louie (San Mateo, Ca.)

Healthy Roots and Watering by Mary Parisi (Pacifica, Ca.)

Observing Haworthia Roots by Peter Taverna (Adelaide, So. Australia)

Recent Publications Compiled by Carol Clapp, The Desert Breeze, Tucson Cactus and Succulent Society

QUIZ TIME by Chuck Staples

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From the San Francisco Succulent and Cactus Society (March &April 1999 newsletter)

The Growing Tip

By Michael S. Louie

Volume 2 Issue 3 - April 1999

'The Growing Tip' is a forum where members and friends of the SFSCS can share information about succulent horticulture, nomenclature, science, history, ethnobotany, and other interesting topics. We encourage readers to submit interesting short articles that they have written or found (with permission and/or proper credit given to the author).

Beneath the Soil

by Michael Louie (San Mateo, Ca.)

Many growers do not concern themselves with plant root health until the tell tale signs of distress become evident: The healthy sheen of the plant dulls from dehydration, turgid leaves or stems become flaccid, and the fine extremities appear wilted. "Did I over-water or under-water?" "Why did the roots die?" Plants have many kinds of roots: deep tap roots that centrally anchors a plant firmly into the ground, lateral moisture seeking surface roots not only offer radial support but also roam great distances looking for moisture to transport back to the main crown of the plant. Feeder roots are specialized roots that fan out as intricate permeating networks that extract nutrients and minerals from the growing media. If any of these roots lose function, the plant will be at risk of starvation, dehydration or losing physical support. Finally the tiniest members of the root family are the root hairs which spread out with great surface area looking for water and nutrients. The hairs injure very easily-even during a bumpy ride in the car to the plant show! The hairs regenerate quickly when a plant is healthy and active to help plants reestablish quickly.

Most succulents benefit from growing in an open, porous medium that offers air, water and essential nutrients. Growers can achieve this by adding large airy particles (pumice, perlite, lava rock...etc) into potting mixes. The amount of time that roots stay in contact with water and air can be controlled by correlating the shape of a pot with its volume capacity. In general, deep, narrow pots give faster drainage than shallow, wide pots. However, watering schedule, climatic conditions and soil mix "openness" are the primary determinants of plant root health.

When a plant is "under-watered," or experiences long periods of drought, the fine feeder roots and surface roots dehydrate and die causing a plant to become flaccid, malnourished and unstable in the growing media. This is also the case when a plant is "over-watered," and the fine roots die of drowning. In both cases, moist dead roots provide a rich nutrient source for opportunistic soil dwelling bacteria and fungi to feast on the root remains sometimes leading to infection of the plant. Pests, such as Sciara fly larvae consider dead moist roots an invitation to feast opening "gateways" for soil microbes to wreak havoc.

In order to maximize the chance for a plant to thrive in a container, a grower should be acquainted with a plant's root structure; understanding the shape, size and extent of the various roots. Growing conditions should accommodate the size and shape of the roots and the medium should fit the air-water contact requirements of the root system. The watering schedule should be such that fine roots are not killed by drowning or excessive dehydration. When the system beneath the soil is healthy, the plant has a chance to thrive and reward the grower with satisfaction and accomplishment.

Happy Growing!

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Healthy Roots and Watering

by Mary Parisi (Pacifica, Ca.)

When a plant's growing media stays bone dry for long periods of time, a plant can lose its feeder roots. These handicapped plants have trouble absorbing water and nutrients and sit in wet soil with the threat of rotting. To make matters worse, plants grown in very small pots dry out very quickly putting feeder roots in jeopardy. I am always trying out new soils and currently testing a heavy soil made up of loam, sand and large gravel. This is very different from the 50%pumice 50% potting soil that I generally use. Many wild plants in nature are often found growing in fine soil combined with small stones. I believe that the stones are the key to success since they can open up the soil to allow for drainage and healthier roots. With heavy soils, it is very important to water lightly and to choose appropriately sized pots. To keep feeder roots healthy in heavy soil lightly water allowing soils to gently dry out in between waterings.

When a plant looses its feeder roots, I place the rootless victim(s) under my indoor grow lights and apply frequent but light watering (sometimes a spray twice a day). The warmth from the lights seems to encourage root development. Plants in habitat do not lose roots the way cultivated plants do, instead, roots die and re-grow just like some leaves do. In the field, many plants develop an underground stalk that doesn't rot out. In pot culture, an underground stalk can be a site for rot when a plant is overwatered. I also put ailing plants (plants which have lost all roots) in open pumice soils (or even pure pumice) after they have dried for a few days. Repotting can also traumatize fine roots and I tend to mist the repotted plants daily to aid water transport until the roots regrow. I still like small pots but only when a heavier soil is used. I like to use a pot that fits the root structure. Many succulents respond well to frequent light waterings. There are many variables that have to be taken into consideration: soil to pot size, pot type (plastic, high-fired clay, low fired clay...), weather, health, air temperature, humidity and root structure. Many succulents fare well when small amounts of moisture remain inside the pot while the surface of the soil is dries after a day or two. If the plant sits in wet soil for a long period then something is usually wrong with the whole plant-soil-pot combination. The plant may have lost its root structure or is dormant. In this situation, misting should be used to keep water contact light. As plants respond favorably to good watering practices, the roots will thrive giving the plant vigor and size. The stems thicken and roots age.

The old roots eventually die and decay furnishing another source of nutrition for the growing plant. I have seen Haworthia in the field that exhibit thick stalks growing deep into the ground--characteristic of old plants. These plants had many sets of roots and slowly lost them to regenerate new ones that continue to anchor the plant to the soil. Root loss is probably a normal part of the life cycle, much like the way some leaves die and are replaced by new ones. The problem occurs when the moisture balance is disrupted by partial or complete root loss or when root rot makes its way up a stem. Although it is interesting to consider how plants grow in nature, one must not forget that rot also occurs in nature. A grower friend once pointed out to me that when light colored gravel or pumice on the surface of his soil became darkish brown in color, this was an indication of problems beneath the soil: root loss and or rot. After hearing this, I tested this theory by selecting out plants for repotting (those with the most discoloration in top dressing) and I found that it was true. In almost every case there was evidence of root loss. Most of the plants were OK, but some had rot in the stem and required emergency surgery.

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Observing Haworthia Roots

Peter Taverna (Adelaide, So. Australia)

I live in the Adelaide Hills of South Australia at an altitude of almost 2000' with 40" of rain during wintertime (June-August). The temps rarely fall below freezing and summers are hot often over 100 F. Most Gasteria will grow in the garden here and almost all Haworthia will survive without overhead protection. Less than 8 mile away in the Adelaide plains, Haworthia can be easily grown in the outdoor garden.

I spent yesterday re-potting plants and have some observations to note. I emptied my H. springbokvlakensis & H. brunysii s and cleaned out all the dead and decomposing roots from the middle of the "fist" of fat finger roots that these plants share with such species as H. emelyae. The thought occurred to me that in the field, these old roots which die off in the center would soon be consumed by little critters and keep the root zone clear. The fact that these dead roots sit for long periods in cultivation probably contributes to the breakdown of living roots in overwatering situations. I took the opportunity to remove most of the outer leaves from all the plants that I barerooted and potted them up 90% perlite 10% potting mix in clear pots. I placed them on a dry hot bed to callus and dry them. Then I give them a fungicide spray. If the temperature is cold, I'll increase the bottom heat and by next year I have pots full of little plants to share. I identify clones by writing their ID number on the leaf with a felt tip pen. Having been repotting of all my plants for almost 4 days for the first time in 5 years, some thoughts come into consideration: the depth of growing pots. I have observed how the deep-rooted species (most species) react when their roots hit the bottom of the container. The "finger" rooted types hit the bottom and force surface lateral roots to travel often out the nearest drain hole of the pot! I think this is a good strategy where many plants in nature must encounter rocks and other impenetrable strata and need to find a way around the obstacle. I have taken my succulent rooted Haworthia species out of 6" deep pots as they seem to be of little advantage and am now growing them in wide shallow containers and very open mix. Proliferous Haworthia species seem to have roots that spread laterally and slowly dividing. Solitary Haworthia seem to have the fat "finger" roots. This doesn't seem to be the case with the green fleshy species, which have shallow roots. The dark, hard-leaved species have deep thick roots. When selecting containers for Haworthia consider accommodating the type and size of roots not just the size of the leaf crown.

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From The Desert Breeze, Tucson Cactus and Succulent Society

Recent Publications

Compiled by Carol Clapp, The Desert Breeze, Tucson Cactus and Succulent Society

Notes on Haworthias. Compiled by Stephen Holloway from articles with black/white pictures published by J.R. Brown from 1934-1974 in the C J and Desert Plant Life. 219pp + card cover. 500 copies only being published worldwide. $27 inc. Available Jan '99.

New Pachypodium & Adenium Handbook by Gordon Rowley. The Cactus File Handbook No: 5. 80pp 109 full color photos, 39 distribution maps. 25% larger format than earlier. Cactus File Handbooks. Fax: +44 1703-893348. $49.95 after May1. Available April '99.

Mammillarias by John Pilbeam. Cactus File Handbook No: 6. Updated and totally expanded version of Pilbeam's earlier work long out of print. All species in full color. Distribution maps and collection numbers. 350 pp. 7; x 10 1/2;hardbound.

Ferocactus by John Pilbeam and Derek Bowdery - another Cactus File Handbook. Expected late 1999.

Mesembs of the World by Gideon Smith et al (inc. Steven Hammer and B.E. van Wyk) Similar type production to van Wyk's Aloes which is proving to be a popular book. A Briza publication also from the National Botanical Institute of South Africa. 701 color photos. $59.95. Scientific key, identification key, cultivation and distribution of mesembs. Available now.

Haworthia Revisited - a Revision of the Genus by Bruce Bayer. This third book on Haworthias by Bruce Bayer will fill a large gap in available literature. This is a major revision of the genus. Has one section "cultivation, propagation and plant health" written by Steven Hammer. ~450 color illustrations, 20 habitat photos, distribution maps. $59.95 US. Was due March, but put back to May.

From Haworth to Haworthia. Produced in English by the Haworthia Society, this is the brochure of the Zurich City Botanical Gardens six-monthly display. Contributors were Bruce Bayer, Urs Eggli, Ernst van Jaarsveld, G. Smith and D.Supthut. Starting in the17th century, the development of the genus Haworthia and related genera is outlined and discussed. It considers the part played by Holland in the collection and study of plants from South Africa followed by that of England after they took over control of South Africa from the Dutch. A summary of Haworth's life is included. Color photos and line drawings. 24pp. $12.95 US. English edition ready now.

Lithops - by Steven Hammer. Guide to cultivation. Includes new cultivars, habitat photos. Historical data, chronology of species, descriptions of all taxa and descendants. Nearly 200 color photos, b/w drawings and a map. 120pp softbound. ~$29.95. Late April'99.

Echinocereus - edited by Lino Di Martino. A supplementary volume to the quarterly journal of the Cactus & Co. International Society. 114pp with masses of color photos. A 'must-have' for Echinocerei enthusiasts. $23.95. English/Italian. Was first available in 1998 but listed here by popular request.

Cactus & Succulents - A Care Manual by T. & S. Mace. $19.95. Ideal for those just starting in the hobby. Really spells everything out. Many pictures. Available now.

Cacti by Terry Hewitt. Good book for beginners who need basic information. 64pp 160 color photos $9.95. Available now.

Succulents by Terry Hewitt. Another good book for beginners with basic information. 64pp 146 color photos. $9.95. Available now.

The Ultimate Book of Cacti and Succulents by Miles Anderson. Similar in form to Terry Hewitt's book, but with more caudiciforms and hardiness information in Fahrenheit applicable to Tucson area, and elsewhere in US. 254 pp. Over 1000 color photos. Should appeal to all levels of expertise. All you need to know about identifying, buying and cultivation of cacti and succulents. $34.95.

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From the Newsletter of the Mid-Iowa Cactus and Succulent Society

QUIZ TIME

Chuck Staples

1. What is the correct spelling of this genus?
a. Mamillaria b. Mammilaria c. Mammillaria d Mamilaria

2. Noted lecturer and author Gordon Rowley is from
a. Germany b. United States of America c. Canada. d. England

3. The Arizona state flower comes from this plant:
a. Cephalocereus senilis b. Carnegiea gigantea c. Fouquieria splendens d. Myrtillocactus geometrizans

4. Which of the following is commonly referred to as "Burn Plant"?
a. Aloe variegata b. Aloe plicatilis c. Aloe ferox d. Aloe vera

5. The genus of species 'grusonii' is:
a. Echinocereus b. Epithelantha c. Echinocactus d. Euphorbia

6. This person was the editor of The Cactus and Succulent Journal for many years.
a. Gordon Rowley b. Rob Wallace c. Seymour Linden d. Charlie Glass

7. This person is currently Treasurer of The Cactus & Succulent Society of America:
a. Pat Fusaro b. Mindy Fusaro c. Seymour Linden d. LoWilla Wilson

8. Who was the first president of CSSA and the year(s)?
a. Andrew C. Stapleton, 1919 b. Howard E. Gates, 1936-37 c. Charles G. Adams, 1933-34 d. Arthur D. Houghton, 1929

9. Where was the first CSSA Convention Site held, and the year?
a. St. Louis, MO, 1929 b. San Diego, CA, 1963 c. Denver, CO, 1951 d. St. Louis. MO. 1941

10. All cacti have spines.
/__/ True /_/ False

11. Which is a species of Astrophytum?
a. myriostigma b. asterias c. ornatum d. all of the above

12. Which of the following is commonly referred to as "Living Rock"?
a. Ariocarpus b.Lithops c. Astrophytum d. Aporocactus

13. Which of the following is commonly referred to as "Living Stone"?
a. Ariocarpus b. Lithops c. Astrophytum d. Aporocactus

14. Which of the following is commonly referred to as "Century Plant"?
a. Agave attenuata b. Agave victoriae-reginae c. Agave americana d. Agave utahensis var. nevadensis

15. Which genus has the stinky flower?
a. Senecio b. Stapelia c. Sulcorebutia d. Sempervivum

16. Which of the following is commonly referred to as "Hatchet Cactus"?
a. Pelecyphora asseliformis b. Pleiospilos bolusii c. Rebutia grandiflora d. Opuntia microdasys

17. Which genus has a cephalium?
a. Mamillopsis b. Myrtillocactus c. Melocactus d. All of the above

18. Cactus plants originated in the New World which is:
a. Australia b. Hawaii c. Madagascar d. North & South America

19. Which is a cactus?
a. Pachypodium b. Pachycormus c. Pachycereus d. Pachyphytum

20. All cacti are succulents, but all succulents are not cacti.
/_/ True /_/ False

Answers to quiz

1. c. Mammillaria 2.d. England 3. b. Carnegia gigantea 4. d. Aloe vera

5. c. Echinocactus 6. d. Charlie Glass 7. b. Mindy Fusaro

8. d. Arthur D. Houghton, 1929 9. d. St. Louis, Mo. 1941 10. False

11. d. all of the above 12. a. Ariocarpus 13.b. lithops

14.c. Agave americana 15. b. Stapelia 16.a. Pelecyphora asseliformis

17.c. Melocactus 18.d. North & South America 19.c. Pachycereus 20. True

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