It was early in the day. I opened my window to let in the very first rays of the morning sun, just to catch a waft of that distinctive floral aroma lingering in the cold air. This year, autumn came early, and hoa sữa has started blooming where I live.

People often refer to hoa sữa as the “muse” of the Hanoian autumn, coating city streets in a layer of pristine white blossoms. Its fragrance is the most pungent element capital residents' collective memory. Every autumn, there are two ways Hanoians would talk about hoa sữa: one shrouded in eager anticipation and dreamy romanticism, and the other is pretty much “I can’t stand it, it’s so annoying.”

Hoa sữa appears frequently in evocations of autumn, in between romanticisms and laments about its concurrently sweet and dizzying smell. No matter how one feels about that, it’s impossible to deny that the flower has become a unique harbinger of the season — an aroma that reminds locals of nostalgia, something that many hold dear.

Hoa sữa, the unofficial muse of the Hanoian autumn. Photo via Tiền Phong.

A familiar flower

Milkwood’s scientific name is Alstonia scholaris, known in some regions as mò cua, but it’s perhaps nationally famous by the name hoa sữa. The name arose because the plant emits an abundant white sap just like milk. It possesses a distinctively powerful fragrance that fills the air every time the northern autumn arrives.

Hoa sữa is an evergreen tropical tree belonging to the dogbane family, with a lifespan averaging a few hundred years old. The tree has a sizable trunk growing upright, reaching a height of 10–20 meters, though a few have grown to 50 meters. Trees produce wide canopies so the species is often planted along streets, in parks and residential enclaves to provide shade. Milkwood likes tropical climates and ample sunlight, and grows fast, so it has been widely planted across Vietnam, especially in Nha Trang, Quy Nhơn and Hà Nội, where hoa sữa is the most densely distributed.

Milkwood has wide canopies, fan-shaped leaf arrangements, and a strong smell. Photo via Wikimedia.

Hoa sữa bloom in clusters with each tube-shaped flower consisting of five petals and five sepals. Flowers are arranged in circular formations that, from afar, look like bouquets  standing out on the green bed of leathery leaves. The sight of these white bouquets swaying in the soft sunlight of an autumn morning is something especially poetic to me. Just one look and I can immediately feel the tender embrace of a new season that’s weaving itself in between the pulses of the city.

Maybe it is that unique, unmistakable scent that has entered the collective memory of the people. It’s formidably strong, reminiscent of lily, but also quite different as it spreads in the cold air of autumn. It can be pleasant to occasionally detect when one’s not paying attention but is suffocating when living right next to it, especially at night.

Hoa sữa bloom in clusters in the Hanoian autumn. Photo via Dân Trí.

Those who grew up in Hanoi and even those who’ve fallen in love with the capital have probably experienced periods of yearning for a moment of relaxing quietude when you sit on the sidewalk sipping milk coffee, munching on green cốm, and sniffing hoa sữa in the atmosphere. Because of this yearning, everytime I hear ‘Nhớ mùa thu Hà Nội’ (On missing Hanoi’s autumns), an unnamed emotion swells within me:

Since when has hoa sữa taken root in Vietnam?

This question was answered by journalist and writer Nguyễn Ngọc Tiến in an essay: “The French planted the first milkwood tree on Quán Thánh Street. They noticed its tall trunk and luxuriant canopies, great to help shade local streets from the searing sun of northern Vietnam. The following years, more hoa sữa were planted along streets like Nguyễn Du. As the trunks often spawn tough protrusions, people used to call it vú trâu [buffalo boob] tree. In the beginning of the 20^th century, hoa sữa were planted sparingly with a gap of 10–15 meters between trees, so when the flowers bloomed at the end of September to October, the fragrance was only gentle, not pungent.”

Since then, hoa sữa has spread across Hanoi’s major streets; Nguyễn Du Street became the unofficial “hoa sữa street,” to the point that many believe that only by being on Nguyễn Du can one grasp how breathtaking (literally) the flowers are. In recent years, the municipal government has cultivated hoa sữa all over town and Nguyễn Du is no longer the sole owner of that title. On Thụy Khuê, Quán Thanh, Cửa Bắc or Đào Tấn streets, one can easily recognize that scent every fall. For a crop of young Hanoians, taking a stroll on the bank of Hoàn Kiếm Lake to catch a touch of monsoon wind mixed with hoa sữa aroma is a yearly ritual.

Rows of milkwood trees in Thái Bình City. Photo via Sài Gòn Tiếp Thị.

Departing from Hanoi, hoa sữa embarked on a cross-country trail to pepper alongside streets in the south. Around October, a stretch of Nguyễn Lương Bằng Street in District 7 of Saigon where it cuts Trần Văn Trà Street is perfumed with the sweet smell of hoa sữa. There are around 20 milkwood trees here, all planted in 1997. Hoa sữa might not be as prevalent in the city as in Hanoi, but if you know where to look, there are spots to relish its distinctive scent. There are a few hoa sữa trees on Hoàng Sa and Trường Sa streets, one in Vĩnh Lộc Industrial Park, and some individual trees in residential areas across town.

Outside of Vietnam’s colder regions or metropolises, I also bumped into hoa sữa during my trips to the Mekong Delta in autumn, like in An Giang. A friend once told me that to get from Ngã Ba Lộ Tẻ in Châu Thành District to Ngã Tư Đèn 4 Ngọn in Long Xuyên City, there are six hoa sữa “checkpoints.” The aroma is most intense around the area of Hoàng Diệu Bridge and Nguyễn Trãi Street. Though the tree and blossoms still look the same, somehow in my mind, it doesn’t have the same grace like those people often rave about in Hanoi. Perhaps it’s because you can take an icon out of its homeland, but you can’t separate the land from the icon.

Hoa sữa and an indictment: guilty or not?

Hoa sữa only does what it evolved to do in nature, but its existence has become victim to much censure by the public.

Fascinatingly, there were quite a number of legal suits involving hoa sữa in history, as those living near flowering trees cannot stand its head-splittingly intense scent. In 2004, locals in Tam Kỳ City, Quảng Nam filed a complaint against the flower, alleging that its pungent smell caused constant bouts of allergy, asthma, and migraine. Residents of Trà Vinh City in the Mekong Delta also once threatened to sue the local people’s committee as the city’s illogical hoa sữa density caused much inconvenience to their livelihood.

Following the uproars in many cities across Vietnam, localities started removing milkwood trees and replacing the plots with other non-flowering trees to reduce the concentration of hoa sữa. Via these incidences, I learned that this is not just a problem unique to Vietnam, but also in a number of other Asian countries where the plant is endemic.

As an evergreen tropical species, hoa sữa shows up in other Southeast Asian nations as well. The newspaper Bangkok Post once wrote a piece suggesting the use of hoa sữa to combat unpleasant smells in the neighborhood. In Indian, local opinions about the tree are also just as polarizing: some think that it’s so aromatic that “no matter how busy one is, they must stop to enjoy it,” but others believe that its intense smell causes a lot of troubles in their daily lives.

Hoa sữa lining local streets. Photo via ivivu.

A government directive from Noida, a city in northern India, reads: “If asthma sufferers stand under a milkwood tree for too long, they can have respiratory problems.” The city has since replaced hoa sữa with purple jarul trees. In Taiwan, over two-thirds of milkwood trees at Chihcheng Secondary School were axed as their scent negatively affected students.

Preserving the fragrance of the Hanoian autumn

Above all, whether they love, hate, or threaten to chop all the trees down, I know that deep inside their hearts, Hanoians still value their role in the city landscape and the memories they’ve built with hoa sữa. In the collective subconscious, there’s always a sense of anticipation before the first blossoms show up, signaling an impending autumn.

To conserve that elegance and ease the people’s discomfort, I think there needs to be deliberate efforts to space out hoa sữa trees to a manageable distance like 50 meters. In reality, some localities went too hard on the planting with just 2–3 meters between trees. By relocating or removing some trees in central areas, the city can still protect one of Hanoi’s most iconic autumn features while ensuring the health of its people.