When to plant hyacinths in Invercargill: by 9 May

In Invercargill, hyacinth: plant by 9 May. The winter here is too mild for our late-planting rule, so we give no later limit.

Hyacinth in Invercargill: soil, season and weather

No month averages below 0 °C at night; the coldest nights, in July, average 5 °C.

Planting	by 9 May
First autumn frost	8 June
Coldest nights	July, 5 °C
Soil back at 1 °C in spring	already in the first week of July
Daylight	9:38 on 9 May
Daylight at the winter solstice	8:35

The same dates in Invercargill hold for Garlic, Tulip, Daffodil and Crocus.

Hyacinth in Invercargill: depth, winter cold, pests and pets

Plant hyacinths 10 cm deep, at least 7.5 cm apart (RHS).

In Invercargill the average daily temperature stays at 10 °C or lower for about 19 weeks a year (our estimate from ten years of monthly weather). For this bulb Wisconsin Horticulture Extension gives a cold period of 12–15 weeks at about 2–10 °C. The winter here gives that in the ground, so the bulbs need no pre-chilling.

Flowers get smaller in the years after planting: for full spikes, replace the bulbs or add a few new ones each autumn (RHS).

If squirrels are a problem, protect the bulbs with wire mesh (RHS). Hyacinths are toxic to dogs, cats and horses: intense vomiting and diarrhoea (ASPCA).

Sources: RHS, Wisconsin Horticulture Extension, ASPCA.

Hyacinth in nearby cities

Around Invercargill, Queenstown is 19 days earlier and Nelson 13 days later.

City	Distance	Date	Difference
Queenstown	154 km	20 April – end of June	19 days earlier
Dunedin	176 km	22 April – end of June	17 days earlier
Timaru	318 km	by 5 May	4 days earlier
Christchurch	464 km	by 6 May	3 days earlier
Nelson	694 km	by 22 May	13 days later
Blenheim	705 km	by 1 May	8 days earlier

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