Hoya peduncles (flower spurs): what they are and why not to cut them

What a peduncle is

A hoya flower cluster is an umbel-like head of star-shaped flowers, each on its own thin stalk (the pedicel), all attached to one stouter stalk: the peduncle. Growers usually call it the spur. Flora of China describes the inflorescences of Hoya carnosa as globe-shaped heads of about 30 flowers on a peduncle about 4 cm long, with pedicels 2–4 cm long ^[5]. Missouri Botanical Garden gives 10 to 30 flowers per cluster for the same species ^[2].

Flora of China describes hoya inflorescences as growing beside the leaf stalks at a node (extra-axillary) or sometimes at the shoot tip, and as producing a succession of flower clusters, so an old peduncle becomes thick and covered in scars where earlier flowers were attached ^[6].

Why you should leave it

The sources agree on this point more than on any other in hoya care:

• Missouri Botanical Garden: keep the flowering stalk once the blooms are over, since the next flowers come from that same old spur ^[2].
• NC State Extension: resist pruning the peduncle, which will produce flowers repeatedly over several years; cutting it off is cutting off future flowers ^[3].
• Royal Horticultural Society: do not deadhead; stalks that stay on the plant often produce further flowers where the old clusters were, and a plant may flower a second time after the first flush ^[1].

Most of this guidance is written about Hoya carnosa or about hoyas in general, but species pages give the same advice for some other species. NParks Singapore says new buds form from the old floral stalks of Hoya kerrii ^[7], and NC State says new flowers form on the old spurs of Hoya lacunosa and that the spur of Hoya pubicalyx flowers over several years ^{[8, 9]}. For other species, the flowering sections on this site say only what their sources record.

What you can safely remove

• Spent flowers. They fall on their own. If they are messy, you can remove them without touching the spur. NC State notes that Hoya kerrii flowers drip reddish-brown nectar that can stain fabrics, walls and furniture ^[4], and that H. carnosa flowers may produce a sticky sap ^[3].
• Weak or crowded shoots. The RHS recommends light pruning in late winter or early spring, cutting just above a side shoot or leaf, and notes that hoyas do not respond well to hard pruning ^[1]. NC State also suggests pruning H. carnosa, if needed, in early spring before rapid growth begins ^[3]. When pruning, step around the spurs.

Wear gloves when you prune: the RHS warns that the milky sap is toxic and can irritate skin ^[1].

Bare stems are not spurs, but keep them too

Hoyas often grow long, leafless, twining stems. These are not peduncles, but they matter for flowering as well: NC State says those of Hoya kerrii should not be cut back, because they come before new leaves or flowers ^[4]. Guide them onto a support instead (see the trellising guide).

When a spur is in bud

Once buds appear on a spur, stability matters. Missouri Botanical Garden advises against rotating or moving the pot ^[2], and the RHS warns that buds may drop if the light level changes or the compost becomes too wet or too dry ^[1]. If your spurs keep failing to produce open flowers, the guide to hoyas that will not bloom covers the other causes.

Checklist

1. Never cut a spur, even when it looks dead.
2. Remove spent flowers by hand if they are messy.
3. Prune only lightly, in late winter or early spring, and work around spurs.
4. Do not move or turn the plant while spurs are in bud.