Outdoor Hydrangea is known as Garden or Landscape Hydrangea and most often belongs to 6 common types of cultivated Hydrangeas: Smooth, Bigleaf, Panicle, Climbing, Oakleaf, and Mountain, you can see their list at the end of this post. Indoor Hydrangea the so-called Gift or Florist Hydrangea, most often belongs to Bigleaf Hydrangea (H. macrophylla). So, Florist and Garden Hydrangeas belong to the same species but what is the difference between indoor and outdoor hydrangea?
Before answering this question, let me ask you “Why do you buy a potted Hydrangea?” undoubtedly, you will say because of its incredible over-the-top blooms. Yeah, but have you ever thought about how they can produce flowers out-of-season? Come on to read a part of the research of Warner Orozco-Obando et al. (2005) about flowering Hydrangea:
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“The general doctrine of flowering in H. macrophylla is that floral induction occurs during the previous season, with the flower appearing the following year (Zhou and Hara, 1988). Plants in their native habitat initiate inflorescences under the cool, short-day conditions of fall, then bloom in spring with the resumption of growth, making its flowering pattern similar to that of azaleas (Bailey and Weiler, 1984). In hydrangea, growth and floral initiation are affected by both temperature and photoperiod as shown in numerous greenhouse studies. Generally, cool temperatures cause flower bud differentiation with 15 to 18 °C reported as optimal for some cultivars (Wallerstein and Runger, 1985). Long days promote vegetative growth while short days promote floral initiation (Bailey, 1989).” |
So, Hydrangeas need to taste all seasons to flower but the main question is still consistent; How can gift hydrangeas produce flowers out-of-season in nurseries? Let’s read a part of the article by Neil Anderson et al. (2009) about flowering indoor Hydrangeas out-of-season:
| “Commercial production of vegetatively propagated liners for use as potted plants (15 cm pots for four flowers; 10–15 cm pots for single flowers) typically follows a schedule of short day photoperiods and cold storage, which mirrors what happens in nature (Dole and Wilkins, 1999). For adequate flower bud initiation and early development, most cultivars require a minimum of 6 weeks at 18 °C (nights) and short day photoperiods (8 h), followed by defoliation plus 6 weeks of cold, dark storage at 4–7 °C (Guo et al., 1995, Post, 1949, Shanks et al., 1986).
Plants are subsequently forced in the greenhouse at 16–17 °C (nights), followed by 12 °C for the final 2 weeks, for spring holidays, such as Valentine’s Day, Easter, Mother’s Day, or Memorial Day (Kurt Weiss Greenhouses Inc, 2001).” |
So, growers force the Bigleaf Hydrangeas to bloom out of season by using specific growing conditions (as you found out above) to sell them with large stunning clusters of pink, blue or white flowers in florists and gardens.
➡ So, an indoor Hydrangea never blooms again in your house unless you provide photoperiod and temperature treatments similar to nurseries. Indeed, the Gift Hydrangeas are not good for much more than temporary decoration. It is while an outdoor hydrangea can flower every summer in your garden for years. It is the first difference between indoor and outdoor hydrangea.
➡ But what will happen if I plant my indoor Hydrangea outdoors? Can it produce its lovely blooms in my garden? unfortunately, unlike outdoor Hydrangea, indoor Hydrangea cannot tolerate hard winters, it is the second difference between indoor and outdoor hydrangea.
However, there are tips for following them you can put the pot of your indoor Hydrangea on a balcony or yard and enjoy its growth and flowers for years, however, it is not easy. I discussed these tips in my other post “Can you Put an Indoor Hydrangea Outside?”.
Don’t forget to ask me your questions and tell me about your gardening problems in the comments. I will help you as soon as possible. Be happy.
Additional information: The list of outdoor Hydrangea
1- Smooth Hydrangea (H. arborescens) such as:
- Incrediball hydrangea (Hydrangea arborescens ‘Abetwo’)
This species is native to the eastern United States. It’s hardy in USDA zones 3-8, making it adaptable to a wide range of climates. It’s more heat and cold-tolerant than other hydrangea types.
2- Bigleaf Hydrangea (H. macrophylla) such as:
- Nikko Blue hydrangea (Hydrangea macrophylla ‘Nikko Blue’)
- Cityline Mars hydrangea (Hydrangea macrophyllaCityline ‘Mars’)
- BloomStruck Bigleaf Hydrangea (Hydrangea macrophylla‘BloomStruck’)
- Eldorado hydrangea (Hydrangea macrophylla‘Eldorado’)
- Eldorado hydrangea (Hydrangea macrophylla‘Eldorado’)
- Madame Emile Mouillere hydrangea (Hydrangea macrophylla‘Madame Emile Mouillere’)
- Miss Saori hydrangea (Hydrangea macrophylla‘Miss Saori’)
This species is native to Japan, China, Korea, and Southeast Asia. Hardiness/climate Bigleaf hydrangeas are cold tolerant to USDA zone 5 and heat tolerant through USDA zone 9 because they are native to mild coastal regions of Japan.
3- Panicle Hydrangea (H. paniculata) such as:
- Limelight hydrangea (Hydrangea paniculata ‘Limelight’)
- Zinfin Doll hydrangea (Hydrangea paniculata ‘Zinfin Doll’)
- Unique hydrangea (Hydrangea paniculata‘Unique’)
This species is native to southern and eastern China, Korea, Japan and Russia (Sakhalin). Panicle hydrangea is hardy and can thrive in USDA zones 3 through 8, making it more cold-hardy than many other hydrangea species
4- Climbing Hydrangea (H. anomala) such as:
- Climbing Hydrangea(Hydrangea anomala petiolaris)
This species is native to the woodlands of Japan and Korea. Climbing Hydrangea is hardy in USDA zones 4-9, making it suitable for a wide range of climates. it is intolerant of hot and humid conditions
5- Oakleaf Hydrangea (H. quercifolia) such as:
- Gatsby Pink hydrangea (Hydrangea quercifolia‘Gatsby Pink’)
This species is native to the southeastern United States. Oakleaf hydrangea is hardy in USDA zones 5 to 9. This adaptability allows it to thrive in a range of climates, from colder northern regions to warmer southern regions.
6- Mountain Hydrangea (H. serrata). Such as:
- Blue Deckle hydrangea (Hydrangea serrata‘Blue Deckle’)
This species is native to the mountain forests of Japan. In terms of USDA hardiness zones, the cold and heat tolerance of mountain hydrangeas is similar to that of bigleaf hydrangeas, zones 5-9.
Elahe Rabiei
Hi, I’m Elaheh. My Academic major is plant protection, and houseplants are my expertise. As a houseplant lover, my house is full of indoor plants and it is my passion to take care of them. Hence, I’m here to share my knowledge and experience about growing healthy houseplants. I am also a plant protection advisor, so feel free to ask me any questions you may have.