Hi All, I'm looking for names of trees and understory plants that are natural, native companion plants to the Catalpa Speciosa (Northern Catalpa aka Cigartree/Catawba/Indian Bean Tree). As well, I'm looking for other plants commercially available in Vancouver that have proven to flourish under its canopy or under the influence of its root system. Fernbush (Chamaebatiaria millefolium) and Buffaloberry (Shepherdia argentea) are two native understory companions I found so far; other than that I haven't had much luck.. Thanks!!
I ended up finding some good answers to this question; attached the Word document along with links in footnotes, in case anyone is interested. (Northern Catalpa) Ecosystem of Origin • Geographic distribution It has been extensively propagated for over 200 years. It can now be found in most states east of the Rocky Mountains and in Utah. Prior to European settlement it was native to a small area of the central Mississippi Valley basin, western Tennessee, northeast Arkansas, the lowlands of southeast Mississippi and southern Illinois and Indiana. It is now readily found from Kansas south to Texas and eastward to Louisiana. Has been able to grow almost anywhere in North America, and has become widely naturalized east of the Rocky Mountains outside of its restricted native range. Found in coastal plains and bottomlands, forest, upland forest, mesic, floodplain forest, wet-mesic, wetland, swamp, border of lake, developed land and restoration forest. • Climate of origin Will not tolerate below -38 degrees F. Intolerant of shade. Needs a minimum 90 frost-free days. It prefers an open sunny space to partial shade. Hardiness: USDA Zone 4a: to -34.4 °C (-30 °F), to USDA Zone 8b: to -9.4 °C (15 °F) Natchez, Mississippi climate is hot during summer when temperatures tend to be around 27 degrees Celsius and cool during winter when temperatures tend to be around 10 degrees. The warmest month of the year is July with an average maximum temperature of 33 degrees Celsius, while the coldest month of the year is January with an average minimum temperature of 3.8 degrees Celsius. The annual average precipitation at Natchez is 157.7 Inches. Rainfall in is fairly evenly distributed throughout the year. The wettest month of the year is March with an average rainfall of 6.74 Inches. Seasonal weather averages for Natchez, Mississippi: http://www.wunderground.com/NORMS/D...Name=Natchez&StateCode=MS&Units=none&IATA=HEZ • Soil conditions preferred by the plant (its niche in the overall ecosystem) Prefers coarse or medium-textured soils (ie. ‘sandy loam’), but not fine. pH should be between 5.5 and 7. Low salinity tolerance. Does not tolerate anaerobic situations. Low calcium carbonate tolerance (ie. of agricultural lime) Tolerates alkaline soil and wind well. • Water / moisture conditions preferred by the plant (its niche in the overall ecosystem) Medium drought tolerance. Min. 20 Max 80 precipitation. Low moisture use. Catalpas prefer moist, deep, well-drained soil, but adapt to dry or wet soils. Because they grow in the Mississippi lowlands, they can adapt to areas that have seasonal flooding. Easily grown in average, medium to wet, well-drained soils. Tolerant of a wide range of soil conditions including both wet and dry soils. Tolerant of seasonal flooding. Prefers moist fertile loams. • All natural companion plants – including companion trees In the Coastal Plain Division in the southernmost section of Illinois, including the bottomlands of the Cache River, Catalpa grows along with swamp chestnut or basket oak (Q. michauxii) Hackberry and basswood grow near catalpa on low dikes in Aghaming, Winona Trees and plants that grow near Catalpa in Lower Mississippi River swamp forests include baldcypress (Taxodium distichum), water tupelo (Nyssa aquatica), button bush (Cephalanthus occidentalis), water ash (Fraxinus caroliniana), water-elm (Planera aquatica), and black willow (Salix nigra) In lower hardwood swamp forests of the Lower Mississippi, Water hickory (Carya aquatica), red maple (Acer rubrum), green ash (Fraxinus pennsylvanica) and river birch (Betula nigra). Understory includes butterweed (Senecio glabellus), jewelweed (Impatiens capensis), and royal fern (Osmunda regalis). Backwater/flats forests include sweetgum (Liquidamber styraciflua), sycamore (Platanus occidentalis), laurel oak (Quercus laurifolia), and willow oak (Quercus phellos), poison ivy (Toxicodendron radicans), greenbriers (Smilax spp.), and trumpet-creeper (Campsis radicans). Closer to the upland forests are oak, hickory and pine. In southeastern floodplains and low terraces of the Mississipi Valley that have gradient streams with sandy and silty substrates, where Catalpa Speciosa is native, the following are known to grow: cypress- gum swamp (bald cypress, pond cypress, water tupelo, swamp tupelo) and bottomland hardwood forest (bottomland oaks, sweetgum, American elm, red maple, green ash, water hickory). Mostly forested wetlands and deciduous forest, some pine plantations and cropland on terraces. • At least 5 natural understorey plants (smaller trees, shrubs, perennials and bulbs) Fernbush (Chamaebatiaria millefolium) and Buffaloberry (Shepherdia argentea) Understory in lower hardwood swamp forests includes butterweed (Senecio glabellus), jewelweed (Impatiens capensis), and royal fern (Osmunda regalis). • At least 5 other plants that complement this tree and are commercially available in the Vancouver, BC area (these are also native companion plants) -Sweetgum tree -Acer rubrum -Oak -Hickory -Royal Fern • Known problems with the tree, including incompatible plants due to tree chemistry (allelopathic effects) NOT a known allelopath Known for heavy, ‘messy’ ornamental litter (flowers in spring, leaves in fall, seedpods in winter). Larva of the catalpa sphinx caterpillar (Ceratomia catalpae) eats leaves. Almost complete defoliation may occur in some years. Immature seeds in the pods are often destroyed by a small yellow grub, the larva of a gnat. Brown leaf spots on leaves are often created by the fungi Macrosporium catalpae. Catalpa is also susceptible to the decay fungus Polystictus versicolor. Powdery mildew causes a white powdery coating on the leaves. When severe the leaves turn yellow and drop. Verticillum wilt will make the branches die, and can eventually kill trees. Catalpa midge (Cecidomyia catalpae Comstock) causes leaf spots, injures terminal buds and branch tips, as well as seeds in the pods. Environmental concerns: It is an invasive, weedy tree which escapes cultivation easily. On young tree seedlings the bark is thin and easily damaged by impact, or rodents.
I find myself wondering why you are asking the question. If it is because you want to establish a garden under or near a mature Catalpa, the type of plants involved won't matter all that much. If you are working in the root and debris zone of the tree, all plants will have trouble getting established and surviving because the Catalpa is a dominant presence. In a natural ecosystem, it may be growing with other plants that seed or otherwise establish themselves into a clearing (after a fire or a tree falling) at around the same time. If you are trying to plant a tree in the root zone of a Catalpa, I am not convinced that one of its natural companions would have much more of a chance than an unnatural one - or put another way, any reasonably vigorous tree may have as good a chance. The Royal Fern too is a plant that can grow in a tree's root zone and debris carpet - but so can some other ferns (probably those with ascending rhizomes). Almost any information pertaining to gardening under large trees will be of use to you too.
Thank you. In answer to your question, the reason I wanted to find the info was because I'm taking a class on ecological landscape design. Each person in my class was assigned one species of tree, and we were required to find companion plants. Each plant will be added to a database the college is (apparently) making, which will help gardeners be able to select plants that are best suited to their environment and neighboring species. After doing that research, I think the chances are fairly low that I'll be planting many Catalpa in the future, mostly because they require a lot of room and are 'messy' with leaf litter. But who knows!
"(apparently)" is good - it will apply to the validity of the database if it gets made, for the reasons I mentioned above. Why do people keep trying to treat an urban environment as if it were a natural ecosystem - and gardeners like idiots? Sigh.
