The Monday Garden, Eco-gardening at its best
May 1, 2005, Issue 162
The northern catalpa (Catalpa speciosa) is a beautiful, tropical-looking North American native shade tree with a mysterious past. At one time, its range was confined to part of the Mississippi Valley but sources are admittedly fuzzy about which part. Likewise, the name is definitely Native American in origin but there's a big disagreement over which tribal language is the source.
RANGE AND FAMILY: Today, the northern catalpa (Bignonia family) is found through out the U.S.A. and southern Canada, as well as in other countries where it has been imported as a combat-ready urban tree. Also found in temperate urban areas are the northern catalpa's southern Appalachian kin, the southern catalpa (Catalpa bignioides), and its Asian kin particularly the clearly invasive empress tree (Paulownia tomentosa). Those of you from the southwest might know the southwestern native cousin, desert willow (Chilopsis linearis). Many gardeners are familiar with the lovely orange-flowered native trumpet vine, which is the family's signature member. The Chinese catalpa (Catalpa ovata) is also sold for landscaping.
picture: Northern catalpa in bloom at Stamford High. Stamford CT June 2004
INVADER OR RETURNING ALUMNI? Some say that outside of its native range, the northern catalpa is an invader. My home state of Connecticut has labeled the northern catalpa as having "demonstrated invasive tendencies", which is a no-no of the third degree. (The first degree has been reserved for the worst of the worst, like ailanthus). Being "invasive" means that the plant doesn't come from the area, can escape cultivation and survive on its own, can spread widely, and can out-compete local native plants.
There is no question that the northern catalpa does not stay where it is planted. My own Hoyt Street Alley hosts numerous northern catalpa specimens both large and small. The northern catalpa's spread, however, is limited by its natural fussiness as to location it likes rich, moist, slightly acid soil and just a touch of shade. In other words, it is an edge-of-forest tree that won't survive in deep forest, and which does well in the open meadow and lawn only with plenty of water, as in the Alley.
But is an invader? How come the northern catalpa is built to withstand the -30F temperatures in Montreal, if its original range was only in the southern Mississippi Valley? The black locust may be similarly situated. Many say the black locust an invader in the Northeast, but geologists have found that black locust was here before the Ice Age. So, the black locust is only reclaiming its original territory. Is the same true of the catalpa? Oddly, it is hard to come by popular-level research publications on the catalpa. The northern catalpa has even been neglected by the U.S. Forest Service, whose web site is normally the source of much good information.
picture: This catalpa, along the Mill River, at Scalzi Park, has been repeatedly cut down by the Parks Department. Stamford CT, April 2005.
Does it play nicely with others? To me, this is the more important question. Regardless of whether the northern catalpa has a pre-Ice Age "green card" permitting it to be outside of the Mississippi Valley, does it add or detract from bio-diversity? Again, popular-level research is hard to come by. Anecdotally, in my area, I have not observed it taking over. It is weedy in that it makes lots of seedling-babies.. However, I don't see pure stands of catalpa where it has crowded out the competition. (I wish that could say the same for certain others such as the ailanthus and Norway maples). In Hoyt Street Alley, the northern catalpa shares space with a variety of trees including the box elder and Norway maples, American elm, eastern cottonwood, red oak, shaggy bark hickory, American sycamore, chokecherry, white mulberry, ailanthus, and native crab apple. The catalpa saplings are hardier than those of most of the other trees (as hardy as the ailanthus in fact), but even the big catalpa trees are being smothered in places by that dreaded invader porcelain vine.
Allelopathic: There is authority that both the southern and northern catalpas are "allelopaths", in that they emit chemicals from their roots that prevent other plants' seeds from germinating. The work done on the southern catalpa indicates that the allelopathic properties only become a problem when the tree is allowed to grow in large, pure stands.
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HUMAN-ANIMAL USE: Naοve America humans used catalpa for medicinal purposes. Their kids, like ours today, probably played with the large heart-shaped leaves, orchid-like flowers and cigar-shaped seed pods.
As early as the 1750's the Euro-settlers recognized the value of the catalpa. The tree grows fast and fairly straight, producing a brittle but rot-resistant, light-weight wood, good for farmers' fence posts and for railroad ties. So where the farmers and railroads went, so did catalpa planters. The catalpa was thus spread over most of the Midwest and Southwest. However, the catalpa, as a native tree, has native predators and, over time, the catalpa did not well commercially because in large, pure stands, the predators get out of hand. The chief predators are "catawba" worms (see below), several non-serious leaf fungi, including powdery mildew, and verticillium wilt, an internal fungus that is a killer.
Today, the northern catalpa is recognized as a useful, fast growing, medium-to-large ornamental shade tree that stands up well to urban pollution. This is despite it being a bit weedy with its seedlings and a bit messy with its flowers, leaves, and seed pods. (Note: There is no such thing as a litter-free tree except over-hybridized, high-pollen male street trees. In my view, if you will tolerate only litter-free trees, get a plastic one, and go live where only plastic trees grow.)
Strangely enough, northern catalpas are also grown for fish bait. No, fish do not eat the tree. But some good eatin' fish do adore the larvae of the catalpa sphinx moth, known as "catawba" worms. The catalpa sphinx moth is a very ordinary looking gray-brown moth whose younger self is a caterpillar with yellow and black longitudinal stripes. The moth is more of a problem (or blessing, depending on whether or not you're a fisher-person) in the south. In any case, when the little guys get going they often completely strip trees of foliage and if they do this several times, they can kill the tree. Meanwhile, both the fisher-person and the birds, and perhaps the fish, enjoy the caterpillars.
Pollinators, including hummingbirds, love the flowers. Few animals munch on the leaves and bark; even the white-tailed deer don't like it much. The thick, shady canopy is good for birds' nests but bad for lawn grasses. Plant it where you'd like a shade garden or a mossy lawn.
As a lawn tree, give it plenty of space and water, and a touch of shade. The leaves will get iron chlorosis (yellow between the veins) in high PH soil.
picture: Northern catalpa in bloom at Stamford High. Stamford CT June 2004
DESCRIPTION: The northern catalpa has big (7-10" or so), heart-shaped, velvety, medium green leaves that are in opposite pairs on the branch or in whorls of three. The leaves are pinnately veined, smooth edged and have soft hair below. Clusters of the showy flowers cover the tree in early summer. The bell-shaped flowers are white with yellow or purple spots, and come in branched, upright clusters. The flowers are followed by long, bean-like reddish-brown seed pods which persist over the winter. The pods split in the fall to release flattish, papery, fringed seeds that can be wind-borne quite some distance.
The tree, itself, is medium-sized with a short, stout trunk, spreading branches, and a rounded crown. The bark is relatively smooth, brown and reddish-brown; and, with age, develops scales and/or shallow vertical fissures.
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IDENTIFICATION CHALLANGES: In the winter and early spring, believe it or not, catalpa saplings can be mistaken for ailanthus and stag-horn sumac saplings that grow in the same conditions. In the summer, catalpas of any size can be mistaken for the Asian invader, the empress tree (Paulownia tomentosa).
The empress tree v. the catalpa is easy to resolve, while both trees have the family's big heart-shaped leaves, both kept their seed pods most of the year. The catalpa, has the long, bean-like pods. The seed pods of the empress tree are ovoid and only an inch or so in size. The empress tree also has purple, rather than white flowers.
Distinguishing ailanthus, sumac and catalpa seedlings is more of a challenge and requires careful observation of the twig's buds and leaf scars.
The catalpa leaf scars are round to oval and there's no terminal bud, so the bare twig looks kind of like a traffic stop light; next year's bud sits on the "shoulder" above the leaf scar and has a rosette of tiny dark, pointed bud scales.
The ailanthus and sumac leaf scars are more heart or shield shaped. The ailanthus' buds are fat, rounded, fuzzy lumps sitting in the notch at the top of the leaf scar.
The sumac's bud is more pointed and is at the center of the leaf scar.
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All three have dramatic new foliage in lime green to dark red. As the leaves come out though, you will be able to tell the catalpa's simple heart-shape from the ferny compound leaves of the ailanthus and sumac.
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Cross breeding: the Southern catalpa and the Asian kin are often sold in the northern temperate area by landscapers, and, guess what? The catalpa trees cross breed. So if the tree you're trying to ID does not quite look like it should, take a look at the foreign cousins you may be looking at a mutt.
picture: Northern catalpa leaf in the rain at Stamford High. Stamford CT, summer 2004
Photo credits: Sue Sweeney
© Sue Sweeney 2005
Comments (30)
Is the Catalpa appropriate as a shelter tree in a horse pasture? Will the leaves, flowers or seed pods cause any health problems for horses or wild life.
Posted by Janis Hogarth | May 29, 2005 12:14 PM
Posted on May 29, 2005 12:14
I'm not aware of it being a problem and my favorite source for animal poisoning issues, Purdue vet school, doesn't list catalpa as a problem for livestock. http://vet.purdue.edu/depts/addl/toxic/cover1.htm
This article from the Canadian government says catalpa's safe around livestock and lists some other good choices:
http://www.gov.on.ca/OMAFRA/english/livestock/horses/facts/info_livestock_pastures_trees.htm
Good luck with tree and horses.
Sue
Posted by S. W. Sweeney | June 1, 2005 6:37 PM
Posted on June 1, 2005 18:37
Thank you for the most detailed article on Catalpas I have yet to find!
Question- I am planting some catalpa seedlings this summer and I am wondering if they need to be coppiced next year the way the paulownia requires coppicing.
Posted by Julie | June 3, 2005 3:54 PM
Posted on June 3, 2005 15:54
I'm glad that you found the article useful.
I'm always amazed that catalpas are natives; they look so tropical. Fortunately, catalpas don't need coppicing or much other care. They'll pretty much self-prune into a graceful heart shape if open-grown or a taller narrower form at the edge of the forest.
I can see coppicing for catalpa's Russian cousin, paulownia, because paulownia wood's so soft (hollow care) that the trees can literally fall apart. However, since paulownia is invasive in North America, it is best to not grow it at all.
Sue
(For other readers of this comment pollarding and coppicing are the regular cutting back of a tree to a knobby stump (called a "stool"), to force the tree to produce new growth useful for firewood, wattles and the like.)
While the catalpa is one tree that was traditionally used in this manner in the Mediterranean, coppicing is not real good for any tree. Left to grow naturally, catalpa form a beautifully shaped mid-sized tree.)
Sue
Posted by S. W. Sweeney | June 8, 2005 11:54 AM
Posted on June 8, 2005 11:54
Quetion???
I have a row of catalpa trees in my backyard. Recently, we cleared out around them. To make it easier for them to grow. What should I fertize them with. Also, two of them seem to have been eaten out of the center by aunts, termites. Can I fill this in with anything, and get a new growth to start. I would hate to have to cut them down.
Posted by kathy | June 13, 2005 2:29 PM
Posted on June 13, 2005 14:29
Kathy--
Most grown trees don't need fertilizer (or pesticides, for that matter). What they do like is mulch and supplemental water during droughts.
Mulch keeps the moisture in, insolates the roots, and provides organic matter. Don't use more than 3" or you'll smother the roots, and leave a space at least 6" wide around the trunk so the mulch doesn't touch the trunk. For more information, see my the article on site about mulch.
Water: Where legal, young trees and ailing trees benefit from extra water during the dry times in spring, summer, and early fall. The "rule of thumb" is 1" water per week for most plants. So when the catalpas aren't getting that much water from rain or the sprinkler system, they will appreciate an extra drink if the ground around them is dry down 2" or 3". (Check with your trowel).
Remember, though, that trees are big, so it takes a lot of water to make a difference. A slow, thorough soak is best. You want to apply enough water to penetrate at least 2" or 3" down under the entire tree out to the "drip line" (where the leaves farthest from the trunk would rip on the ground). Once every week or two is enough -- over-watering is worse than under-watering. Repeated, light waterings that only get into the top 1" or so of soil encourage the tree to be shallow-rooted (bad!) so make sure to water less often but deep.
Pests: I'd let nature take its course with where ever's eating some of the trees' heartwood. The bugs that you are seeing are often the symptom of a more serious problem as a healthy tree usually doesn't have insects eating out the trunk. Also, the known cures are generally worse for your over-all environment than the loss of the trees, as awful as that is. Also, many arborists now believe that the trunk fillers and sealers cause more problems than they solve. If you've cleaned out around the trees, mulch and water, that's the most you can do for them.
Ailing trees: How bad are the stricken trees? Check the bark all around the trunk from the ground up to make sure that it is firmly attached and looks alive. Check the major branches for parts that haven't leafed out. (Lower and inner branches that get too much shade die naturally). If most of the tree looks OK, it may live for years despite the critter-condo in its core.
You can prune 100% dead wood at any time of year. So if you only have a couple of smaller bad branches, you could have them pruned out to improve the trees' looks and help control rot.
On the other hand, if the trees are in sad shape, it might be best to let them go -- trees don't do revival well and the attempted cures (fertilizers, bug killers, etc) can be expensive, ineffective, and not all that good for your over-all environment. The trees might perk up on their own now in a year or so that you've given them more light and air, and hopefully, some mulch. So I'd give them a chance to get better unless they are potentially dangerous (could fall on the house, etc).
Even if the trees are dying, if they won't fall on anything, consider leaving at least one of them in place, your woodpeckers and other small friends would be very grateful.
Replacements: In any case, it would probably be a good idea, though, to let a couple of the catalpa's seedlings grow so that they can eventually replace the stricken trees.
Good luck with your trees and let me know if I can help you further
Posted by s sweeney | June 13, 2005 4:45 PM
Posted on June 13, 2005 16:45
I am in Zone 5 - upstate NY and have 2 very large, approx 30 yr old Catalpas in my small suburban yard. Whiteflies have been very fond of one for years, though not usually a problem til late in the season. This year, it appears aphids have taken it over. The deck & birdfeeders are sticky from honeydew. I typically use systemic insecticide on my plants late in the season before I bring them indoors, but I don't want to affect the birds, hummers and happy insects by doing so now, so early in the season. What can I use - at least on my deck plants, now all affected as well, so as not to kill the ladybugs and hummers? Thanks!!!
Posted by Dee | June 26, 2005 5:11 AM
Posted on June 26, 2005 05:11
Dee -- "birds, hummers and happy insects" -- you must have a great garden!
We're having a bumper crop of aphids this year -- whole parts of the Mill River's banks by me are sticky with honeydew from the aphids in the Norway maples. Yuk! If you look at my site today, though, you'll see pictures of the ladybugs enthusiastically making more ladybugs to handle the crisis.
Hose off the deck and the deck plants. Repeating the hose treatment about weekly should keep the aphids off the house plants. Don't forget the undersides of the leaves.
It would be good to turn the hose on the catalpa, too, if you can. When we knock the little critters off the tree, they often get eaten by other little critters before they can climb back up. The hose will also annoy the white flies. (Grin)
The white flies, and now the aphids, are a message to you that something is not right with the tree. As you know, bugs in trees are a sign of a weak immune system, just like a cold signals that a human's immune system is weak. A tree's system is weak when it doesn't have the cultural conditions that it needs. Hopefully, the issue is something that you can easily correct. However, the first job, and hard part, is the figure out what the problem is.
Take really close look at both your catalpas, and see if you can see anything different about the one that gets bugs. For example, is the tree with the bugs more in the shade or getting less water? Is it closer to the house and, therefore, getting less air circulation or root room or getting too hot from white siding reflecting the sun? Are the trees the same size, and do their leaves and trunks look the same?
If you can't see anything, is it possible there's a difference underground? For example, if the trees were originally from a nursery, the ailing one might not have had its roots properly spread when it was planted. Does one tree have more roots under the lawn than the other? Could the soil have been compacted by heavy equipment at some point in the past?
Also, have you ever had the soil tested? If not, it's cheap and easy. So take separate samples from around each tree and compare the results.
By the way -- do not reach for the fertilizer. Feeding a sick plant is like feeding a human that's having a heart attack -- feeding encourages growth and that takes energy that the plant doesn't have any to spare right now. Mulching (up to 3") is always good for a tree, and supplement water (when the ground's dry) can save a sick one.
One other note: I don't use any type of poison, systemic or otherwise, on plants being brought into the house. If this concerns you as it does me, try skipping the poison and instead, sinking the plants, pot and all, in water up past the pot rim and soaking for half hour or so to drown the hitchhikers in the soil. You can add a drop of dish washing soap to the water. Also, give the plants' tops a good hosing at least once, if not twice, about three days apart before bringing them in and then repeat as often as you can for the next month or so. Also remember to bring the plants in around Sept 1 so they have plenty of time to adjust to indoors before the heat goes on.
If what's going on with our catalpa isn't oblivious once you start looking, let me know and maybe we can figure it out together.
Sue
Posted by S. W. Sweeney | June 26, 2005 9:41 PM
Posted on June 26, 2005 21:41
We had a wind storm about a month ago (Minnesota)and it took down one of our Catalpas. I don't know the age, but the trunk is quite large. The trunk and most of the limbs were hollowed out (rotted), but the tree had plenty of leaves and provided lots of shade. Is the rotting common or normal?-that's what everyone tells me.
Thank you for providing the best site on Caltalpas.
Posted by sheldon | July 19, 2005 4:59 AM
Posted on July 19, 2005 04:59
Sheldon--
I'm glad that you're finding The Monday Garden useful. Heart rot is not generally reported as a problem with catalpas. However, as mentioned, catalpas haven't been studied all that much. From my childhood, I associate catalpas with big black ants and the frass (sawdust) that ants make when tunneling in a tree with a rotten core, so I think heart rot is part of its natural process. Your tree, though, demonstrates that catalpas are good at living a long time with this problem.
What are you going to plant in the catalpa's place?
Sue
Posted by S. W. Sweeney | July 20, 2005 8:32 AM
Posted on July 20, 2005 08:32
Hello Sue,
Thank you for your response. Believe it or not...there were not one, but two Mountain Ash trees growing inside the Catalpa; one at ten feet and another at about twenty feet. The lower one is sixteen feet tall (replanted); the tap root had to be cut rather short, in order, to replant. I'll know in the spring if it's going to survive. The other one about six feet tall was removed with tap and root ball intact and is doing very well.
The Catalpa answered your question on it's own... I left most of the stump in the ground, as I wanted my lawn to heal before going any further (2 & 1/2 cords of wood). I left for a trip last weekend and upon returning discovered a 20" mass of growth from the healthiest part of the stump. It is the Catalpa. I compared the leaves with the other on the north side of the house.
All the trees in my yard are quite large and the house is 100 years old. The base and the trunk, of the fallen Catalpa, is four feet in diameter and it was between fifty and sixty feet tall. I am not sure if it's possible, but I assumed all the trees were planted around the time the house was built.
Interestingly enough; The city widened our street last year and our neighbor had five Catalpas, on the boulevard, that were removed. I witnessed the stumps at that time and all five were hollowed out. The common belief around here is that; The nutrient requirement for such large leaves forces the Catalpa to rot from the inside to feed itself???
Posted by sheldon | July 20, 2005 10:23 PM
Posted on July 20, 2005 22:23
What a marvellous idea you had to create this page on catalpas. I find it very informative and well-written.
However, my catalpa is very sick (more than half is now dead)and when I inquired to have it cut, the man told me that catalpa wood is poisonous and that each time he fells one, his team get sinus infections. The man also stated that one cannot burn catalpa wood, again because it is poison.
I find this difficult to believe, more so because the contractor doesn't charge more to cut a catalpa than a maple tree or an other tree of similar size.
Is this poison story about catalpas true?
Posted by Christiane Tremblay | July 24, 2005 4:38 PM
Posted on July 24, 2005 16:38
Christiane --
I'm sorry that your catalpa's dying. I grew up with a catalpa, in farming country, and never heard either problem mentioned, nor have I seen a reference to either on the web. It's a new one on me. However, it's always possible, though, that the tree man knows something that the rest of us need to know.
Sue
Posted by S. W. Sweeney | July 25, 2005 10:36 AM
Posted on July 25, 2005 10:36
Fantastic and thorough article! I recently had a cottonwood removed from my back yard both because I'm horribly allergic to the cotton and because it was heaving up the driveway in many places. And it was only around 20 feet tall.
I have two catalpas (northern) in my front yard and a healthy new sapling growing in roughly the same spot the cottonwood was in. I'm considering letting it grow to provide the needed shade and to add some life to the backyard again. I'm wondering if in a few years the catalpa will be heaving up the driveway the same way the cottonwood did? It seems that the roots are quite straight and deep, but I want to make sure.
Any information you have would be greatly appreciated!
Thanks,
Jess
Posted by Jess | August 5, 2005 7:16 PM
Posted on August 5, 2005 19:16
Sorry I don't have this information about catalpas. I can tell you that the catalpa across the street from me is not heaving their driveway.
The driveway at my building is being heaved by honey locust trees but I think the problem may be that the growing conditions are encouraging shallow roots, not the type of tree planted. See for example thees article about compacted soil and similar problems: http://www.hort.cornell.edu/uhi/outreach/csc/article.html and http://64.233.161.104/search?q=cache:JWKfB9cnCrcJ:www.ces.ncsu.edu/fletcher/programs/nursery/metria/metria5/m56.pdf+tree+wells+heaving+street&hl=en
A couple of years ago, at the Brooklyn Botanic Gardens Plant-o-rama, I saw a demo of a new kind of grating for street trees that would help the tree keep its roots from heaving sidewalks but I wasn't able to locate the vender for you by Goolge search. If anyone knows this vendor, please email.
Sue
Posted by S. W. Sweeney | August 6, 2005 11:31 AM
Posted on August 6, 2005 11:31
i have two empress trees growing in the backyard and am wondering if they are poisonous to my dogs. they love to eat the bark and sometimes even the hugh leaves. Thanks for your input
Posted by jean denman | November 21, 2005 10:33 AM
Posted on November 21, 2005 10:33
I have 2 catalpa's on each side of our driveway, that I have pruned over the years so that they each hava a "knob" about 7 feet from the ground. I always prune them back to the trunk (about 7' tall) and they grow back to provide a 6' - 7' umbrella each year. Here's my issue. I planted a red maple about 8 feet away from 1 of the trees. After about 5 years the maple and 1 of the catalpas are touching and the the appearance looks crowded. Can I cut the 2 catapla trunks horizontally at about 5'? This would keep them under the branches of the maple tree. Will cutting the cataplpas this way kill them?
Posted by John | March 12, 2006 12:36 PM
Posted on March 12, 2006 12:36
John -- I've never tired this particular maneuver, so I can't be sure, but the generally accepted principles of tree botany say that there's a good chance the tree will NOT recover. Some thoughts:
If you're going to do it, do it early in the spiring (now) so the tree has the best chance to recover and do it with the idea that if you didn't do this, the tree would have to come out anyway.
I'd definitely do the one that has to come out first and see what happens before touching the other one (next year).
If the maple will be shading the catalpas, and blocking their air circulation, it might be best to take them out anyway in the next couple of years.
Consider consulting a local arborist before making the first cut.
Hope this helps.
Sue
Posted by S. W. Sweeney | March 12, 2006 6:07 PM
Posted on March 12, 2006 18:07
Hi ,
What an amazing site!!
My question is ,that I am about to start seedlings for the Catalpa tree ,(northen).
I am starting them in pots indoors,this is a first for me(lol),
Do I put the seedlings in soil first or under a wet paper towel to start ,and do i plant the seedling standing vertically or horizontally?
Posted by She | April 5, 2006 5:01 PM
Posted on April 5, 2006 17:01
Sorry, I don't know and the usual references don't say.
What I would do is try a few each way. Catalpa self-seeds well (too well some would say), so I doubt it is all that particular.
Good luck.
Sue
Posted by S. W. Sweeney | April 10, 2006 10:18 AM
Posted on April 10, 2006 10:18
Glad to find the info on catalpa trees. My wife works at a local historic farmstead that just had a (very!) hollow southern catalpa removed that was overhanging a carriage house. I had collected some seed pods last fall. This spring I placed 3-4 seeds per 4" pot on potting medium, then covered the seeds with a dusting of soil.
So far nearly 100% germination, so I'd agree that they must not be too fussy!
Posted by Michael Bell | May 31, 2006 3:54 PM
Posted on May 31, 2006 15:54
This has been a very helpful site! We have a catalpa tree in our backyard that is looking like it is about to die. It did the same thing last year but came back this spring. It started on one of the branches with the leaves turning yellow, wilting, and then dying. It then spread to the rest of the tree. We live in Missouri and it has been very dry here. Is that the problem or something else?
Thanks Kelly
Posted by Kelly | June 29, 2006 10:40 PM
Posted on June 29, 2006 22:40
Can someone please tell me what happens to the Catalpa worm after it eats all the leaves and it seems to just disappear over night.We live in Alabama and my brother has these trees on his land and he ask me to research where the worms go or what happens to them when all the leaves are gone. We have been told a wasp or a moth lay the eggs that hatch into a caterpillar.Which one?
Okay I hope someonne will email me with an answer. Thanks so much. bjg518@mon-cre.net
Posted by bjg518 | July 10, 2006 5:53 PM
Posted on July 10, 2006 17:53
Help, my catalpa is apx 18 feet high and healthy, about 4 years old, but I just noticed today the leaves are drying out in patches on the tree is this symptom of something worse? we have had really hot days (plus 35 degrees) but the tree is irrigated and bark mulched, both top and lower growth of the branches and leaves seem ok, flowering is finished and we are zone 6 BC Canada, any suggestions?
Posted by mindy | July 22, 2006 5:55 PM
Posted on July 22, 2006 17:55
Kelly -- it could be the drought or it could be a much more serious problem like the fungus verticillium wilt, which can kill the tree.
If the tree is valuable, you might want to do some in-depth research on catalpa disease yourself (See e.g. http://web1.msue.msu.edu/imp/modzz/00000303.htmlAt to get started) or consult a professional arborist to get a diagnosis.
If it is verticillium wilt, pruning out the dead parts is said to help. If you do prune, be sure to clean your cutting equipment with alcohol or 10% chlorox after cutting each affected branch so as not to spread the fungal spores. I've heard that reports are mixed on whether fertilizer helps or hurts a tree with verticillium wilt but, in my view, slowly deteriorating organic mulch is all the fertilizer a tree usually needs.
In any case, once you have a diagnosis, make up your own mind about using any type of concentrated chemical to treat the infection, balancing the tree's value against that of the entire environment (including you and your kids, the local bird and insect population).
Whatever the problem, 1-2" of fine mulch, rather than lawn or paving, over the tree's roots is always the best thing you can do for a tree. Plus, for a young or sick tree, during droughts, add 1" per week supplemental water, allowed to slowly sink in, out to the tree's drip line.
Hope this helps
Sue
Posted by S. W. Sweeney | July 24, 2006 3:10 PM
Posted on July 24, 2006 15:10
good question about the worms
Sorry but I don't know the answer as we don't have the worms (really caterpillars, I think) up here in the North. My suspicion, though, is that, since the tree and worms evolved together, once the worms have finished their tree munching, they go make their cocoons.
In the bug world, bug-eat-bug is the norm, so probably some of the worms are preyed upon by other insects as you suggest, as well as by birds and fishing-humans.
I have a similar case up here of some caterpillars which look like army worms (but there are so many kinds of caterpillars I'm hesitant to say for sure what they are). Anyway, they show up in my mother's garden every summer, strip the yellow loosestrife bare and disappear. I really don't like yellow loosestrife -- much too weedy for my tastes -- but I keep some so as to not disappoint the caterpillars.
Sue
Posted by S. W. Sweeney | July 24, 2006 3:12 PM
Posted on July 24, 2006 15:12
I to Have two catalpa trees and am attempting to start more from the seeds or from cuttings... any suggestions or instructions?
Posted by Jeanie | August 4, 2006 1:32 PM
Posted on August 4, 2006 13:32
Just 2 questions, I recently had to cut 2 Catalpa trees down, First is the wood good for firewood, or would it be good to cook with in an outside bbq or smoker?
Posted by Dave | August 9, 2006 6:37 PM
Posted on August 9, 2006 18:37
Dave -- catalpa is rated as "Fair" quality firewood -- it's not very (like willow) so doesn't do a nice slow, hot burn like oak. So I don't know if I'd use it indoors 'cause I don't know whether it would build up in the chimney like pines do.
This Utah site has the details:
http://extension.usu.edu/forestry/HomeTown/General_HeatingWithWood.htm
Posted by Susan Sweeney | August 10, 2006 8:49 AM
Posted on August 10, 2006 08:49
Jeanie -- Catalpa cuttings should root readily. If not, put a piece of will twig (high in growth hormones) in the water. The seeds also have a high fertility rate. Using cutting can get you a year or two ahead on size.
If you don't get good cuttings now, spring is the best time.
Sue
Posted by Susan Sweeney | August 10, 2006 9:06 AM
Posted on August 10, 2006 09:06