How to Grow and Care for Peonies in the Toronto Area
Peonies are cold-hardy perennials well-suited to USDA zones 4–8. Since Toronto is located in zone 5b, it provides an ideal climate for growing peonies.
1. Common Types of Peonies
Herbaceous Peony
This type is best suited for Toronto’s climate. It is drought-tolerant, easy to care for, produces abundant blooms, and comes in a wide range of colors. Herbaceous peonies die back completely in winter and regrow in spring. No winter protection is needed. Some varieties have soft stems that may need support to prevent flopping when in bloom.
Tree Peony (Paeonia suffruticosa)
Also known as mǔ dān (牡丹) in Chinese, this is a deciduous woody shrub. The above-ground stems do not die back in winter and grow taller year after year. The flowers are large and showy. Tree peonies can be grown in Toronto but require some winter protection, especially around the roots and bud nodes.
Itoh Peony (Intersectional Peony)
Itoh peonies are hybrids between herbaceous peonies and tree peonies, originally developed by Japanese breeder Itoh Masato in the 1940s. He died shortly after the initial hybridization, and American breeders later continued developing and popularizing these plants. Itoh peonies are also known as intersectional peonies. They are very well-suited to Toronto’s climate and do not require winter protection.
Although the blooms resemble tree peonies, the plant itself has a herbaceous structure — it dies back in winter and regrows in spring. Compared to herbaceous peonies, Itoh peonies have a longer bloom time, rich flower colors, and stronger stems that resist flopping.
2. Sunlight Requirements
Peonies require full sun — at least 6 hours of direct sunlight per day. Insufficient sunlight can lead to fewer or no blooms.
3. Soil Conditions
Peonies prefer well-draining, fertile soil with a slightly acidic to neutral pH (6.5–7.0).
Before planting, enrich the soil with compost or well-aged organic matter to improve structure and fertility.
4. Planting Time and Method
Best planting time: Fall (mid-September to mid-October), giving roots time to establish before winter.
If planting in spring (May or June), use potted peony plants with leaves already sprouted, not bare root.
When transplanting, keep the root ball intact and plant it directly into the ground with the soil.
Planting depth: Peony “eyes” (buds) should be 1–2 inches (2.5–5 cm) below the soil surface. Planting too deep may prevent blooming.
Spacing: Space plants 2–3 feet apart to ensure good air circulation and reduce disease risk.
Add a thin mulch layer (like wood chips) to retain moisture, regulate soil temperature, and encourage root development.
5. Watering
In the first two years after planting, keep the soil evenly moist but not soggy.
Once established, peonies are relatively drought-tolerant. During the blooming period or heat waves, water deeply once a week.
6. Fertilization
Apply a balanced slow-release fertilizer in early spring after new growth appears.
Apply again after blooming to help the plant store energy in the roots.
Avoid overusing nitrogen-rich fertilizers, which may result in lush leaves but no flowers.
7. Winter Protection
Herbaceous and Itoh peonies: No special winter protection is needed. Once the foliage dies back, cut it to the ground to maintain cleanliness and prevent pests/disease.
Tree peonies: After the leaves fall, clean up the area. Before the first hard frost, wrap the base of the plant with frost cloth or burlap and apply a light mulch over the root zone.
8. Pruning and Support
After blooming, remove spent flowers to prevent seed formation and conserve energy.
If the plant grows tall and heavy, use stakes or peony rings to prevent flopping.
9. Pest and Disease Control
Poor airflow and overwatering may cause botrytis blight (gray mold).
Aphids may also appear and can be removed with water or insecticidal soap.
About ants:
It’s common to see ants on peony buds. Peonies secrete sweet nectar that attracts ants — they are not harmful to the plant or buds, and no treatment is needed unless ants become a nuisance indoors.
If ants and aphids appear together, rinse off the aphids with water or use a gentle insecticidal spray — controlling aphids will naturally reduce ant activity.
10. Bloom Time
Peonies typically bloom from mid-May to mid-June, with flowers lasting 1 to 2 weeks.
在多伦多地区种植和养护芍药属植物的方法
芍药属植物适应寒冷气候，适合在USDA 4-8区生长，多伦多属于5b区，很适宜芍药属的植物生长。
1. 芍药的常见种类
草本芍药（Herbaceous Peony）：最适合多伦多的气候，耐旱，易养，开花多，花色丰富。在冬季芍药的地上部分会完全枯萎，到来年春天再发芽生长。不需要冬季防护。一些品种的枝条较软，开花时容易倒伏，需要用支架支撑。
木本芍药（Tree Peony, Paeonia Suffruticosa），也就是牡丹：是多年生落叶灌木，地上的枝干在冬天不会枯萎 ，还会逐年长高，花朵大且华丽，可以在多伦多种植，但是冬季需要做一些防护，尤其需要保护根部和芽点。
伊藤芍药（Itoh Peony, Intersectional Peony）：是草本芍药和木本牡丹的杂交品种，最初由日本育种家伊藤政登（Itoh Masato）在20世纪40年代杂交培育，因此称为伊藤芍药Itoh Peony，伊藤在完成杂交后不久就去世，真正让这个品种发扬光大的，是美国的育种者将其继续繁育推广，伊藤芍药也称为Intersectional Peony。伊藤芍药很适合在多伦多地区种植，不需要冬季防护。伊藤芍药的花型像牡丹，但植物结构是草本的，在冬季地上部分会枯萎，到春天再生长。伊藤芍药的花期比草本芍药更长，花色丰富，花朵挺立，不易倒伏。
2. 光照要求
需要全日照，每天至少6小时直射阳光，光照不足会导致开花少或不开花。
3. 土壤条件
喜欢排水良好、肥沃的土壤，土壤pH值微酸性或中性（pH6.5 – 7.0）
种植前可加入堆肥或者腐熟的有机质改善土壤结构。
4. 种植时间和方法
最佳种植时间：秋季（9月中-10中），这样根系可以在冬季前长好。
在春季（5月6月）种植的话，最好使用已经发芽长叶子的盆栽苗，不要用干根（bare root）。
栽种时不要打散根团，连根带土一起种入地里。
栽种深度：芍药的芽眼不要种太深，离地表1到2英寸（2.5到5厘米），种太深有可能会影响开花。
种植间距：每株相隔2到3英尺，保持通风良好，减少病害发生。
地面覆盖一层薄薄的木屑，可以保湿保温，有利生根。
5. 浇水
种植后头两年保持土壤稍湿润，避免积水。成熟植株耐旱能力强，花期和高温期每周浇一次透水即可。
6. 施肥
春天发芽后施一次平衡型缓释肥，花后再施一次，帮助根部积累养分。
避免氮肥过量，否则会只长叶片不开花。
7. 冬季保护
草本芍药和伊藤芍药：不需要特别防寒，冬天自然枯萎时把地上部分修剪掉，保持干净，减少病虫害的发生。
木本芍药（牡丹）：冬天落叶后，把落叶清理干净，冷天来临前用防寒布包裹根部，在土壤上面铺一薄层木屑。
8. 修剪和支撑
开花之后剪除残花，避免种子消耗养分。
植株长得高大时，可以加支架，以防倒伏。
9. 病虫害防治
通风不良、浇水过多容易有灰霉病（Botrytis），也有可能有蚜虫。
芍药的花苞在形成过程中会分泌蜜露，常常会吸引蚂蚁爬到植物上，蚂蚁只是来采食这些蜜露，不会伤害花苞，数量不多就无需处理。如果看到蚂蚁的同时还有蚜虫，用水把蚜虫冲走，或用杀虫喷雾。
10. 开花时间
通常在5月中下旬到6月中旬，持续约1到2周。
Source from chat.openai. Organized by Qiuye. Not for reprint. 不得转载！