After a summer of growth, a Swiss cheese plant may send long aerial roots from its stem nodes and beyond the rim of its pot. Before treating those unfamiliar lines as something to remove, it helps to remember that this plant is a climbing vine that uses roots as part of its upward growth. Looking at the direction of the stem, the position of a support, and the available indoor light together makes the September decision calmer and more precise.
Aerial roots belong to its climbing form
Plants of the World Online from the Royal Botanic Gardens, Kew records Monstera deliciosa as a liana and hemiepiphyte native from Mexico to Guatemala. The Royal Horticultural Society also explains that the plant climbs trees in the wild and uses roots from its stems to attach and support that growth. An aerial root indoors is not a spare organ detached from the leaves. It is the plant's growth habit appearing in a container.
Without support, a plant can become top-heavy as it produces more foliage. The RHS recommends training stems onto a moss pole, which can give the plant support and allow roots to enter the pole when its moss is kept moist. Guidance from the University of Connecticut likewise lists stakes and moss poles once the vines lengthen. Both sources point toward the same approach: provide the whole plant with something to climb before treating one aerial root as the central problem.
Choose the support before choosing what to remove
Begin by viewing the pot from the front and side, noting the base of the main stem, the direction of the heaviest foliage, and the nodes producing aerial roots. If adding a support, place it where it can hold the main stem without forcing the leaf stalks into a tight bundle. A firm, curved aerial root may break if it is pulled sharply, so leave room for new growth to approach the support gradually. If the pot is unstable, check its weight and location before adding height.
For a moss pole, the RHS advises keeping the moss moist so roots can eventually enter it. Moistening the support and watering the potting mix are separate decisions, however. Check how dry the mix has become, preserve drainage, and do not leave the pot standing in water. Keeping the mix constantly wet simply because an aerial root is long may increase the risk of root rot.
The primary references reviewed here do not support a universal rule to cut every aerial root or to place every one in the potting mix. The goal may be to prevent contact with a walkway or wall, reduce the size of the plant, or train it upward. First ask whether support and placement solve the problem. If pruning is still needed, consider the size and growth cycle of the entire plant rather than one root alone.
September is a time to observe before a major cut
The RHS broadly places the growing season from April through September and recommends pruning an oversized Swiss cheese plant in spring. Those dates come from indoor cultivation guidance in Britain and should not be transferred mechanically to every home in Japan. They still offer a reason to record lean, leaf development, and the drying rate of the mix before a major late-season cut. Unless damage or disease requires urgent action, a support trial can show where the next growth goes and inform a spring pruning plan.
Bright, indirect light is the basic placement. A sudden move into strong direct sun can damage leaves, while very low light can slow growth. On the day a support is installed, avoid combining it with repotting, feeding, and a major light change. Separating changes makes the plant's response easier to interpret. A short record of new leaves, the distance between stem and support, and the time the mix takes to dry can guide the next decision.
The RHS also notes that a climbing Monstera may produce larger, more mature leaves. A pole alone does not guarantee leaf size or fenestration; light, temperature, root condition, and maturity also matter. A support is best understood not as a device for forcing larger leaves but as a framework that respects the plant's climbing habit while keeping it stable indoors.
Follow one line back to the whole plant
A conspicuous aerial root can reduce the question to a simple choice between keeping and cutting it. The form of a Monstera, however, comes from the relationship among stem, node, aerial root, leaf, light, and support. A photograph from the same angle once a week can show how the stem sits against the pole. The long line then becomes a record of direction rather than waste. September does not need to finish the shape. It can reveal what should be adjusted when spring growth begins.