Aesculus flava, or yellow buckeye, is not native to Ontario, originating just south from the Appalachian region of the eastern United States. This tree can be difficult to find in the nursery industry. This native species is tolerant of a wide range of soil types from well drained coarse soil, to poorly drained clay soil, as well as alkaline soil tolerant. Its bloom in the spring attracts a wide range of pollinators. The rich dark green leaves rarely suffer from leaf scorch and end their growing season with shades of pumpkin, salmon pink or red. Unique to the yellow buckeye is its fruit not having spikes.

Aesculus glabra, or Ohio buckeye, is native to Ontario and ranges throughout the western and lower Great Plains regions of the United States, extending southeast into the Black Belt of Alabama and Mississippi, with a small, isolated population in southwestern Ontario. It prefers well-drained, moist soil, and can tolerate higher pH levels. Ohio buckeye can be commonly found in the nursery industry. They are well suited for remote landscapes such as parks, open spaces, or woodland areas but can be difficult to transplant due to the presence of a taproot. Ohio Buckeye is messy, producing spiky seeds and leaf litter and is not recommended to be planted along streets or residential areas as the nuts are poisonous, and when the tree is bruised can emit an unpleasant odour.

CAUTION: INVASIVE TENDENCIES. Aesculus hippocastanum, or common horse chestnut, is non-native to Ontario with a natural range in the Balkans in Europe. Cultivars are commonly found in the nursery industry but are not recommended to be planted in urban settings as it produces poisonous nuts and may have invasive tendencies adjacent to naturalized areas. This species grows in nearly any urban soil, including alkaline soils. They are resistant to most diseases and pests but are prone to leaf scorch, powdery mildew, bark and leaf blotch (not serious threats). The species is considered extremely messy, producing prickly seed pods and bark debris, but cultivars such as Aesculus hippocastanum (Baumannii), are available where the fruit is nearly absent and can be a better choice for urban street tree plantings. The horse chestnut is related to the Ohio buckeye and is easily distinguished by its spiny fruit and sticky buds. It is difficult to transplant but does demonstrate tolerance for clay texture, alkaline pH, and road salt soil, while producing stunning spring flowers.

Aesculus pavia, or red buckeye, is a non-native species, originating in southeastern United States. This tree species is valued for its vibrant flowers and versatility in the landscape. While it's not commonly found in the nursery trade, the ruby-red horse-chestnut (cross between horse-chestnut and red buckeye - Aesculus x carnea) offers a similar alternative and is more widely available. It can grow in well-drained soil to dry soil with full sun to part shade, but prefers moist, fertile soils. While it is considered messy due to its spiky seed pods and toxic nuts, it excels as a specimen tree, screen, or hedge. Although it's challenging to transplant, red buckeye tolerates a range of conditions, including occasional drought and road salt.

Aesculus x carnea, or red horse-chestnut, is a hybrid tree resulting from the cross between horse-chestnut and red buckeye that is commonly found in the nursery industry. It prefers moist, well-drained, acidic soils, but can grow in slightly alkaline soil. It is less susceptible to leaf blotch and mildew than horse-chestnut and red buckeye but is still prone to these diseases. Red horse-chestnut as a hybrid produces fewer nuts compared to other Aesculus species. They are difficult to transplant due to their taproot and may require additional irrigation to help it establish in more urban areas. A cultivar, the ruby horse-chestnut, has nearly absent seed pods that make them a better alternative in urban street plantings, while the more common cultivar is the Ft McNair 'Fort McNair' horsechesnut.

RESTRICTED SPECIES: INVASIVE. Ailanthus altissima, or tree of heaven, is not recommended to plant, due to this species being highly invasive, spreading underground and via seeds. They are non-native to Ontario, originating from China and North Vietnam. This tree can grow under a variety of soil conditions including poor and rocky soils, but prefers well-draining soils. Despite the tree of heaven's bright colours and name, this species is currently illegal to plant in Canada. It spreads aggressively, inhibits surrounding plant growth, and attracts both the invasive Spotted Lanternfly, which threatens grapes and the wine industry and the invasive brown marmorated stink bug. With weak wood, it's prone to storm damage and pests like bagworms and Japanese beetles. It also creates a mess with its litter and emits an unpleasant odour when its bark is scratched. A more suitable species to plant instead is Celtis occidentalis, which are readily available in the nursery industry.

NOT RECOMMENDED TO PLANT: INVASIVE TENDENCIES. Alnus glutinosa, or European alder, is not recommended to plant, due to invasive tendencies. This species is non-native to Ontario with a natural range in Europe, western Asia, and North Africa, and rarely found in the nursery industry. It prefers moist to wet soils, with a pH between 6.0 and 8.0, with an ideal soil composition being a mix of clay, silt, and sand. It is known to be aggressive and overshadow native trees, altering soil chemistry and biology that makes it challenging for native species to grow. Although it is occasionally planted for soil rehabilitation on degraded sites, it poses a significant threat to wetland and riparian habitats. As an alternative, consider planting Betula papyrifera.

Alnus incana ssp. rugosa or speckled alder, is a low, clump-forming shrub or small tree that is native to Ontario and ranges throughout eastern North America and is best suited for moist, open areas. Speckled alder can tolerate clay soil, dry sites, occasional flooding, and wet sites, but not prolonged flooding. This species requires slightly acidic, to neutral pH (7.0), and will become chloric in alkaline soil. It is commonly found in the nursery industry and is a wonderful alternative to the European alder. The stunning species serves as a larval host for the Green Comma butterfly.

Amelanchier arborea, or downy serviceberry, is native to Ontario and ranges throughout eastern North America. This species is valued for its showy clusters of flowers and is often used ornamentally. However, it is rarely found in the nursery industry and is moderately difficult to transplant with its slow root system growth. It grows best in moderately fertile and well-drained soil that is slightly acidic. It prefers a multistem growth form in full sunlight sites, but can grow a single trunk in partially shaded areas. The downy serviceberry thrives in woodland edges and naturalized settings, making it an excellent choice for urban landscapes, though it does not tolerate pollution well. The berries produced are edible and have hybrid cultivars between downy serviceberry (Amelanchier arborea) and allegheny serviceberry (Amelanchier laevis).

Amelanchier canadensis, or shadblow serviceberry, is native to Ontario and ranges throughout eastern North America. This species is a visually striking understory tree that captivates throughout three seasons: with fragrant spring flowers, edible purple berries, and vibrant red and orange foliage in the fall. It prefers well-drained, slightly acidic soils and tolerates full sun to partial shade. It is commonly found in the nursery industry and does not have severe pest or disease issues. The tree is somewhat salt-tolerant but is not well-suited to urban soil conditions or heat island planting sites. It is moderately resistant to deer, tolerant to occasional flooding or wet sites and is often found growing in clumps, making it suitable for woodland and forest environments. It is moderately difficult to transplant.

Amelanchier laevis, or smooth serviceberry, is native to Ontario and ranges throughout northeastern North America. This species is an easy-to-grow understory tree that offers year-round interest with its attractive features. It thrives in medium, well-drained soil, particularly loams, and part-shade or full sun and is classified. Known for their edible berries, they grow at a medium to fast rate but are sensitive to drought and relatively short-lived. Occasional pruning to remove older branches will keep the tree vigorous. It can be challenging to transplant and spring transplanting with care for the roots is recommended for best results.

Amelanchier x grandiflora, or apple serviceberry, is a hybrid species between the Downy serviceberry (Amelanchier arborea) and Smooth serviceberry (Amelanchier laevis), both native trees to Ontario. It prefers medium moisture, well-drained loam soil, and full sun to part shade. It is susceptible to heat and drought, with shallow roots that benefit from mulch to retain moisture and regulate temperature. It is mildly deer-resistant and attracts birds with its fruit. The tree is generally free of major insect and disease issues, though it may occasionally experience powdery mildew and it can be difficult to transplant.

CAUTION: MAY HAVE INVASIVE TENDENCIES. Aralia spinosa, or devil's walking stick, is non-native to Ontario and ranges throughout the southeastern United States. It spreads aggressively through rhizomes, suckers, and is self-seeding, making it unsuitable for small spaces. It can tolerate a wide range of soils. While it prefers moist humusy soils, it will grow in rocky and clay based soils. It also tolerates urban pollution. Handling the plant can cause allergic skin reactions, and it is mildly poisonous if ingested. Regular removal of root suckers is necessary to control its spread. While it faces minimal pest or disease issues, it is susceptible to leaf spots and has large, sharp thorns on its stems. The plant is moderately messy, with seasonal fruit, leaves, and seeds dropping. Although it tolerates urban pollutants, it should be planted in sheltered areas to avoid wind damage.

Asimina triloba, or pawpaw, native to Ontario and ranges throughout eastern North America, is a small understory tree known for its striking purple flowers and large, edible fruit that resembles bananas in flavor and consistency. However, the fruit can be poisonous when unripe, and the seeds contain alkaloids that can cause vomiting. It can tolerate occasional wet or moist soil conditions, but prefers well-drained, acidic soil. The tree faces minimal pest and disease issues but can be messy with large seasonal fruit, leaves, and flowers dropping. It is a good choice for damp areas along ponds and streams and can grow in partial shade.

Betula alleghaniensis, or yellow birch, native to Ontario and ranges throughout eastern Canada to Minnesota and south along the Appalachians to northern Georgia. It reaches heights of 60 to 75 feet and thrives in full sun to partial shade. This species prefers rich, moist, acidic soils, and it is well-suited for forests or streambanks in cooler regions. While it tolerates some alkaline and wet sites, it struggles in hot, dry conditions. This low-maintenance tree provides aesthetic and ecological value, making it an excellent choice for residential landscapes, parks, and naturalized areas.

Betula lenta, commonly known as sweet birch, is native to Ontario and ranges throughout eastern North America, specifically from southern Maine westward to southern Ontario, and south through the Appalachian Mountains to northern Georgia. This species is best suited for residential and park settings. Hardy in USDA Zones 3 to 8, birches prefer moist, well-drained soils but can tolerate a variety of soil types, including alkaline and clay soils. This tree can reach heights of 40 to 75 feet, and is recognized for its strong wintergreen scent when its leaves or bark are crushed. Birch trees are attractive, resilient trees that provide ecological benefits and versatile uses in landscaping and commercial applications. Although this species availability is rare in the nursery, with proper seed collection this species can become more available.

Betula nigra, commonly referred to as river birch, is native to the Eastern U.S. This species is a fast-growing birch known for its striking exfoliating bark. It can tolerate various soil conditions including sand, loam, and clay, but prefers moist well-drained soils, and is tolerant of occasional periods of drought once it has established. A popular and common cultivar in the nursery is Heritage (Cully) and Dura Heat (BNMTF), offering enhanced heat and drought tolerance, a pyramidal form, and vibrant pinkish-orange bark. Dura Heat is resistant to pests like the bronze birch borer and aphids, and performs well in warmer climates with superior bark color and foliage resilience. Both cultivars are well-suited for urban landscapes, though they can be moderately messy with fallen seeds and leaves. Planting single specimens in groups will result in longer life.

Betula papyrifera, also known as the paper birch, or canoe birch, is a beautiful, Ontario-native tree known for its striking white bark. It thrives in acidic, moist, well-drained soils and full sun. While resilient, it can be susceptible to pests and diseases like bronze birch borer, aphids, and leaf miners, though Renaissance cultivars offer slightly greater resistance to the borer. Paper birch prefers cooler, dry conditions and may struggle in warmer, humid environments or urban areas with high pollution. With proper care, it adds elegance to many landscapes as a specimen tree. White birch should not be a first choice for planting in urban conditions unless space is provided to plant several.

NOT RECOMMENDED TO PLANT: INVASIVE TENDENCIES. Betula pendula, or European white birch, is recommended to plant with caution as this species is highly susceptible to bronze birch borer. This species is non-native to Ontario with a natural range in Europe and Asia. It prefers well-drained, moist soils, but can also tolerate dry, sandy soils and can adapt to different soil pH levels. While it may seem visually appealing, its aggressive growth habits make it problematic in many landscapes. It also struggles in hot, humid climates, making it difficult to maintain in many regions. Additionally, its bark sheds, and it produces messy fallen leaves and seed clusters. With its aggressive nature, high maintenance needs and vulnerability to pests, this tree is often best avoided in favor of more resilient native alternatives, like Betula nigra.

Betula populifolia, or gray birch, is a resilient, narrow, pyramidal tree native to Ontario and cooler climates in southeastern Canada (Quebec to New Brunswick and Nova Scotia) and south through New England and upstate New York to Pennsylvania and New Jersey. Reaching 20 to 40 feet, it features striking chalky white bark with dark chevron patterns, enhancing any landscape. Thriving in poor, well-drained soils, it tolerates both dry and wet conditions, making it versatile for diverse environments. With moderate resistance to the bronze birch borer, it performs best in full sun and is ideal for residential areas, parks and naturalization areas. It naturally spreads through self-seeding and creates beautiful stands, while its subtle flowers and drooping cone-like fruits add interest. Though it may shed bark and produce fallen nutlets, its unique appeal and adaptability make it a great planting choice.

CAUTION: MAY HAVE INVASIVE TENDENCIES. Caragana arborescens, or Siberian pea-tree, is not recommended to plant due to its tendency to spread aggressively. This species is a non-native, hardy, low-maintenance shrub from Siberia and China, often used as an understock for decorative cultivars. While it is resilient and tolerant of heat, wind, cold, salt, and poor soils, it is not recommended for planting due to its reputation as a messy shrub in Ontario. The plant's prolific seed production can lead to dense seedling populations, and its small thorns can be an unexpected inconvenience. However, its early leaf sprouting and extended photosynthesis period give it a competitive advantage over other plants and is tolerant of heat, wind, cold, salt, and poor soil conditions.

Carpinus betulus, or European hornbeam, is non-native to Ontario with a natural range in western Asia and the European Pyrenees. European Hornbeam is a deciduous tree that, while adaptable and low maintenance, may not be the best choice for planting. It requires moist, well-drained soil for optimal growth, preferably loam, or sandy loam. It grows to 30 to 60 feet, offering good shade and visual appeal, but its rapid reproduction could lead to overpopulation in certain areas. While it is generally pest and disease-free, it's mostly used as a hedge in landscapes.

Carpinus caroliniana, or Blue-beech, is native to Ontario and ranges throughout the eastern United States and extends into Canada in southwest Quebec and southeast Ontario. Carpinus caroliniana makes an ideal understory tree that reaches 20 to 35 feet. Known for its distinctive, muscle-like fluted bark and attractive globular form, this slow-growing deciduous tree thrives in part to full shade and prefers moist, well-drained soils. Tolerating periodic flooding, it's often found along streams and in rich woodlands but also does well in upland sites and gardens. With low maintenance needs and few pest or disease issues, it makes a great addition to residential, park, or naturalized landscapes.

Carya cordiformis, or bitternut hickory, is native to Ontario and ranges through eastern North America, specifically from southwestern New Hampshire and southern Quebec, west to southern Ontario, central Michigan, and northern Minnesota, and south to eastern Texas and northern Florida. It prefers well-drained, moist soils and does well in full sun to part shade, but has demonstrated good drought tolerance in the summer. This magnificent tree reaches 50 to 80 feet, offering a broad, columnar shape and irregular crown. Thriving in a variety of habitats, from moist valleys to dry uplands, this resilient tree is free from major pest or disease issues. Known for its impressive shade canopy, it tolerates occasional flooding and salt spray. Though moderately messy in fall due to fallen nuts that are bitter and inedible as well as its leaf drop, its benefits make it a valuable addition to any landscape. Currently limited availability in the landscape, but with proper seed collection can become more available.

Carya glabra, or pignut hickory, is native to Ontario and ranges throughout eastern United States and Canada. This species is a large canopy tree, typically growing 50 to 80 feet tall with a rounded crown. Thriving in full sun to part shade, it prefers well-drained, moist soils and tolerates a range of conditions, including occasional drought. Pignut hickory provides valuable wildlife habitat but is susceptible to pests like hickory bark beetles, twig girdlers and pecan weevils. With a long taproot, transplanting is difficult, but easier done in spring. While it produces bitter, inedible nuts and husks in the fall, it remains a beneficial tree for landscapes with no other cultivars. Currently limited availability in the landscape, but with proper seed collection can become more available.