Are Hops and Cannabis Related? The Botanical Connection

Hops and cannabis are not just related but are each other’s closest living relatives. Both belong to the family Cannabaceae, and molecular studies consistently place the genus Humulus (hops) and the genus Cannabis as sister groups that diverged from a common ancestor roughly 21 to 28 million years ago. Their kinship runs deeper than taxonomy: the two plants share a remarkably similar chemical toolkit, the same inherited sex-chromosome system, and even the same viral pathogen. What looks like a quirky piece of botanical trivia turns out to have real consequences for growers, brewers, and researchers working with either plant.

How Close Is the Family Tree?

Both hops and cannabis sit inside Cannabaceae, a relatively small plant family that also includes hackberries and a handful of tropical trees. Within that family, Humulus and Cannabis are sister genera, meaning they share a more recent common ancestor with each other than either does with any other living plant group. Nuclear DNA analyses consistently recover this pairing with strong statistical support, even when the relationships among more distantly related members of Cannabaceae remain debated.¹

When did the two lineages split? A genome-scale analysis of the hop cultivar “Cascade” estimated the divergence between Humulus and Cannabis at roughly 22.6 million years ago, with a 95% confidence interval spanning about 16 to 29 million years.² To put that in perspective, hops and cannabis are roughly as far apart in evolutionary time as humans and Old World monkeys, which is close enough for many shared biological features to remain intact but distant enough for each lineage to have developed its own distinct chemistry.

Their closeness is even visible at the bench. Intergeneric grafts between hops and cannabis, in which a stem of one species is physically joined to the rootstock of the other, remain viable. That kind of graft success across two different genera is uncommon in the plant world and reflects a deep compatibility in vascular anatomy and growth physiology.³

The Trichome Connection

If you have ever handled a fresh hop cone or a cannabis flower, you have noticed the sticky, aromatic resin that coats each one. That resin comes from glandular trichomes, tiny mushroom-shaped structures that sit on the surface of the female flowers of both plants. These trichomes are the factories where each species produces its economically important compounds: the bitter acids and aromatic oils prized in hops, and the cannabinoids and terpenes that give cannabis its pharmacological effects.⁴

Plenty of plants produce trichomes, but the particular style found in hops and cannabis is strikingly similar in structure and gene-expression patterns. Recent comparative genomics work has looked at which genes are switched on specifically in the trichomes of each species and found that the two plants share a recognizable set of active pathways for building their resinous metabolites. This makes them a useful comparison pair for scientists trying to understand how glandular trichomes evolved and how they might be engineered in the future.

Terpenes They Have in Common

The distinctive aromas of hops and cannabis are dominated by terpenes, a broad class of volatile molecules built from repeating five-carbon units. In both plants, terpenes can account for roughly 3 to 5 percent of the dry mass of the female flower.⁵ The specific terpenes involved overlap considerably. Myrcene, humulene, beta-caryophyllene, and linalool are abundant in both hop cones and cannabis flowers. This is why certain hop-forward beers can smell uncannily like cannabis, and why some cannabis strains carry a distinctly “hoppy” or herbal note. The resemblance is not coincidental; it reflects shared biosynthetic machinery inherited from their common ancestor.

From a chemical standpoint, the terpenes in both plants are relatively simple monoterpenes and sesquiterpenes built from two or three isoprene building blocks.⁵ It is the proportions and minor variations that differ between the two, not the fundamental chemical vocabulary. A hop cone rich in humulene and a cannabis flower rich in the same compound are producing the same molecule through homologous enzyme pathways.

Terpenophenolics and Where the Chemistry Diverges

Beyond simple terpenes, both hops and cannabis produce a more complex class of compounds called terpenophenolics, which are hybrids of a terpene-derived side chain bolted onto a polyketide-derived phenolic ring. The bitter alpha-acids in hops (like humulone, the molecule that gives beer its characteristic bitterness) and THC in cannabis are both terpenophenolics. They are assembled through a shared catalytic pattern: first a polyketide backbone forms, then a prenyl (terpene-derived) group is attached, and finally the molecule is cyclized or decorated into its final shape.³

This is where the two plants part company, though. Cannabis has evolved a specialized branch of this pathway that produces cannabinoids like THC and CBD, compounds that interact with the human endocannabinoid system. Hops never developed that branch. Instead, hops specialized in producing bitter acids and prenylflavonoids like xanthohumol. So while the underlying assembly line is recognizably the same, the end products are quite different. The confusion that sometimes circulates online, that smoking hops could get you high, stems from a misunderstanding of this point. Hops do not contain THC, CBD, or any cannabinoid. The shared chemistry is upstream of the molecules that produce psychoactive effects.

A Shared Sex-Chromosome System

Both hops and cannabis are dioecious, meaning individual plants are either male or female. This is relatively unusual in the flowering plant world, where most species produce both male and female organs on the same individual. What makes the hops-cannabis case remarkable is that the two genera share the same pair of sex chromosomes, and those chromosomes clearly date to before the lineages split.

Researchers who assembled phased sex-chromosome genomes for both species found that the X and Y chromosomes share a common origin predating the divergence of Humulus and Cannabis more than 36 million years ago. The Y chromosome in both species is highly degraded, having lost many of its original genes, while the X chromosome shows faster rates of molecular evolution.⁶ An earlier study mapped hundreds of sex-linked genes in hops and found they preferentially corresponded to genes on the cannabis X chromosome, confirming that recombination between the X and Y had already stopped in a shared ancestor at least 21 to 25 million years ago.⁷

This is the first documented case in flowering plants where two different genera share a single sex-chromosome system that predates their divergence.⁷ The finding matters beyond taxonomy because sex determination controls flowering patterns and resin production in both crops. Interestingly, the actual sex-determining gene does not appear to sit on the Y at all. Instead, an X-linked gene involved in ethylene biosynthesis appears to control the development of female flowers, which has implications for breeding programs in both plants.⁶

A Shared Pathogen That Plagues Both Industries

Hop latent viroid, known by the abbreviation HLVd, is a tiny infectious RNA that was originally described in hop plants, where it often causes no visible symptoms but quietly reduces the content of bitter acids and terpenes in hop cones. In 2019, the same viroid was identified in cannabis plants in California, where it causes a condition growers call “dudding.” Affected cannabis plants produce stunted, loose flowers with dramatically lower cannabinoid and terpene concentrations, essentially stripping the crop of its commercial value.⁸

The viroid’s ability to jump between these two genera is a direct consequence of their close relationship. The cellular machinery that HLVd exploits to replicate is similar enough in hops and cannabis that the viroid thrives in both hosts. Making matters worse, HLVd is disturbingly persistent and easy to spread. It can survive for four weeks in dried plant material at room temperature. It spreads through contaminated tools, through recirculated nutrient solution in hydroponic systems, and even through seed. In one study, seeds harvested from infected female plants gave rise to 100 percent infected seedlings.⁹

The shared vulnerability means that best-management practices developed for hop yards, such as testing stock plants before propagation and sanitizing cutting tools, are directly relevant for cannabis growers and vice versa. The viroid also moves faster under short-day lighting conditions, the same photoperiod growers use to push cannabis into flowering, which accelerates the problem precisely when the crop is most commercially valuable.⁹

Combined Terpene Effects in the Lab

Because hops and cannabis produce overlapping sets of terpenes, some researchers have started asking whether combining compounds from both plants could produce additive or synergistic biological effects. One laboratory study tested the anti-inflammatory activity of cannabidiol (CBD) alongside terpene-rich hop extracts in cultured immune cells. The combination reduced markers of inflammation more effectively than either CBD or the hop extract alone, and the effect was comparable to that of hydrocortisone, a standard anti-inflammatory drug. The hop terpenes also appeared to increase the uptake of CBD into the cells in a dose-dependent manner.¹⁰

This is a preliminary finding from a cell-culture study, not a clinical trial in humans, so it would be premature to draw health conclusions from it. But the result is consistent with the broader idea that terpenes can modulate how cannabinoids behave, sometimes called the “entourage effect” in cannabis research circles. The evolutionary overlap between hops and cannabis terpene profiles makes hops a convenient and legal source of these aromatic molecules for researchers exploring such interactions.

Why Archaeologists Struggle to Tell Them Apart

The close botanical relationship between hops and cannabis creates a specific headache for archaeologists trying to reconstruct ancient plant use. Pollen grains from the two genera are morphologically similar enough to be easily confused, which means that when ancient pollen identified as Cannabis turns up at an archaeological site, it could actually be Humulus, or vice versa.¹¹ This ambiguity complicates the story of when and where humans first cultivated cannabis, particularly in regions of Central and East Asia where wild hops also grow. Some researchers have turned to seed morphometrics and ancient DNA to get around the pollen problem, but in many older excavation records the identifications remain uncertain.

The confusion is not limited to microscopy. In the written historical record, early European herbalists sometimes grouped hops and cannabis together or noted their resemblance without clearly distinguishing them. Both were used in traditional medicine across Eurasia, and the similar leaf shape and growth habit (both are vigorous climbing or twining plants) reinforced the perceived connection long before anyone understood their shared lineage at the molecular level.

Synthetic Biology at the Intersection

The shared biosynthetic pathways of hops and cannabis have caught the attention of synthetic biologists. Because the terpene-producing enzyme pathways in both plants are well characterized, researchers have been able to transplant individual genes from these pathways into microorganisms like yeast and bacteria. One team engineered brewer’s yeast to produce the key monoterpenes that give beer its hoppy aroma, eliminating the need for actual hop additions during brewing.¹² More broadly, yeast and E. coli have become favored platforms for producing plant-derived terpenoids, including molecules originally found in cannabis and hops.¹³

This work is driven in part by practical economics. Growing hops is water-intensive, and cannabis cultivation faces regulatory barriers in many jurisdictions. If the key flavor or therapeutic compounds from either plant can be produced by fermentation in a steel tank, supply chains become simpler and cheaper. The deep molecular homology between hops and cannabis means that lessons learned engineering one plant’s pathway in yeast often apply directly to the other, accelerating progress on both fronts.

Common Misconceptions

Perhaps the most stubborn myth is that hops contain cannabinoids. They do not. No peer-reviewed study has identified THC, CBD, or any classical cannabinoid in Humulus lupulus. The aromatic similarity between a dank IPA and a bag of cannabis comes entirely from shared terpenes like myrcene and humulene, not from any psychoactive overlap. Marketing for certain hop-derived supplements has muddied this by implying a cannabinoid connection, but the chemistry does not support it.

A related misconception is that grafting cannabis onto hop rootstock (or vice versa) can transfer cannabinoid production to the hop plant. While the grafts do survive, grafting does not move the genetic instructions for cannabinoid synthesis from one plant to the other. The cannabis scion continues making cannabinoids; the hop rootstock does not start. The graft compatibility is botanically interesting as proof of close kinship but does not create a hybrid organism with merged chemistry.

Finally, the fact that both plants are dioecious sometimes leads people to assume that “feminized” seed technology developed for cannabis could be applied identically to hops. The underlying sex-chromosome system is indeed shared, but hops and cannabis have been bred under very different commercial pressures for centuries, and the specific techniques used differ in practice even if the genetic basis of sex determination is the same.

Growing Side by Side

In practical agriculture, the kinship between hops and cannabis has real implications for anyone growing them in proximity. Beyond the shared susceptibility to HLVd, both plants are attractive to several of the same insect pests, including spider mites and aphids. Powdery mildew species that affect one can sometimes colonize the other. Growers who rotate between hop and cannabis production on the same land, or who grow both simultaneously, need to be aware that disease and pest pressure from one crop can carry over to the other in ways that would not occur between unrelated plants.

On the flip side, the shared biology means that integrated pest management strategies, resistant cultivar development, and biocontrol agents tested in one crop are often worth evaluating in the other. The hop industry has decades of accumulated research on disease management that the comparatively young legal cannabis industry can draw from. In regions where both crops are grown commercially, such as the Pacific Northwest of the United States, this cross-pollination of agronomic knowledge is already happening informally among growers and extension services.