Yes, different lavender varieties can and do cross-pollinate in cold climates, just as they do in warmer climates. The mechanism of cross-pollination (transfer of pollen by bees and other insects) is not dependent on temperature, but rather on the presence of flowering plants and active pollinators.
Here's why and what it means for cold climate growers:
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Pollinator Activity: As long as temperatures are warm enough for lavender to flower and for bees and other pollinators to be active, cross-pollination will occur. Many cold-hardy lavender varieties (like English Lavenders such as 'Munstead' and 'Hidcote') are well-adapted to bloom in colder zones during the summer when pollinators are abundant.
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Genetic Mixing in Seeds: If you have different lavender species or varieties (e.g., Lavandula angustifolia 'Munstead' and Lavandula x intermedia 'Phenomenal') growing near each other in a cold climate, and they flower concurrently, bees will transfer pollen between them. The seeds produced by these plants will carry genetic material from both parent plants.
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Offspring Variability: If you collect and plant these cross-pollinated seeds, the resulting plants will not be identical to either parent. You will likely see a range of characteristics in the offspring, including variations in flower color, plant size, bloom time, and even scent profile. This is why commercial growers and hobbyists who want specific, consistent lavender varieties propagate them from cuttings, which are genetic clones of the parent plant.
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Natural Hybridization: This process of cross-pollination is how natural hybrids like Lavandin (Lavandula x intermedia, a cross between L. angustifolia and L. latifolia) came into existence. In cold climates, if you have these parent species growing near each other, you could theoretically see similar hybridization occur.
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Impact on Essential Oil (as discussed previously): For those growing lavender for essential oil in cold climates, cross-pollination is generally beneficial for increasing yield (more essential oil due to better seed set). However, if maintaining a very specific chemical profile (e.g., high linalool/linalyl acetate and low camphor for true L. angustifolia oil) is critical, growers might still take measures to isolate fields or rely heavily on propagation from cuttings from proven mother plants to ensure genetic purity.
So, in summary, the cold climate itself doesn't prevent cross-pollination of lavender varieties. As long as the plants are flowering and pollinators are present, the genetic exchange will happen, leading to diverse offspring if grown from seed.
