Hyacinth 'Delft Blue'

Questions about hyacinth 'Delft Blue'

Does hyacinth 'Delft Blue' need sun or shade?

Hyacinth 'Delft Blue' grows in full sun (6 or more hours of direct sun a day) and part sun (4 to 6 hours of sun, including some afternoon sun).

It wants ordinary well-drained soil, of average fertility, and a good soak in dry spells. Once settled in, it stands drought.

What zones does hyacinth 'Delft Blue' grow in?

USDA zones 4 to 8. It is hardy to zone 4, which means it survives winter nights down to about −20 °F (−29 °C).

Above zone 8 it struggles: the zones measure winter cold, but a plant's top zone usually means the summers are too hot or the winters too mild for it to rest.

Gardening in Canada? Use the USDA zone for your town: Canada's own zone map uses different numbers.

When does hyacinth 'Delft Blue' flower in my zone?

In zone 5 it flowers mid April to early May. As a spring flower it moves about a week for every zone: earlier where it is warmer, later where it is colder.

Worked out from Hopkins' bioclimatic law: spring arrives about four days later for each degree of latitude north, and one zone is roughly two degrees. A warm spring or a cold one moves any garden two weeks either way.

How far apart should hyacinth 'Delft Blue' be planted?

5 in (12 cm) apart, from the middle of one plant to the middle of the next. That is about its full width, so each plant keeps its own outline.

It grows 10 in (25 cm) tall. Give it the full distance from anything taller, or it will lean out towards the light.

How many hyacinth 'Delft Blue' plants do I need?

At 5 in apart, set out in staggered rows:

• 74 to fill 10 square feet (about 1 m²)
• 26 for a single row 10 ft (3 m) long
• 238 to fill a 4 × 8 ft bed on its own

In a mixed border, plant it as handfuls of five or seven, in the gaps between other plants.

In the bed above, the planner used 10 in two groups.

Is hyacinth 'Delft Blue' poisonous to dogs and cats?

Yes: moderate toxicity to people, dogs, cats and horses. The bulbs are the most poisonous part and cause drooling, vomiting and diarrhoea if eaten. Handling the bulbs can irritate skin.

Rated from NC State Extension and the ASPCA. Where references disagree, the more cautious rating is used.

Is there a pet-safe plant like hyacinth 'Delft Blue'?

These come closest to doing what hyacinth 'Delft Blue' does, and no toxicity is recorded for them:

• Grape hyacinth: the same job in a bed, the same flowering time and the same colour; 4 in shorter, fine leaves, not medium.
• Spring starflower: the same job in a bed, the same flowering time and the same colour; 4 in shorter, fine leaves, not medium.
• Checkered lily: the same job in a bed, the same size and the same flowering time; purple or white, not blue, fine leaves, not medium.

Matched the way the planner's Swap button matches plants: the same job in a bed, then size, then flowering time.

Do deer eat hyacinth 'Delft Blue'?

Mostly not. NC State lists it as resistant to deer and rabbits. No plant is proof against a hungry deer in a hard winter, but this one is low on the menu.

What can I plant to hide hyacinth 'Delft Blue''s leaves after it flowers?

A bulb's leaves have to be left to yellow for about six weeks after flowering, to feed next year's flowers. Plant it among perennials that come up late and spread wide, and they grow over the leaves as they fade:

• Lady's mantle: 18 in tall and 24 in wide, in flower late May to early July.
• Catmint 'Walker's Low': 24 in tall and 2½ ft wide, in flower mid May to mid September.
• Garden chrysanthemum: 24 in tall and 24 in wide, in flower mid September to late October.

What does hyacinth 'Delft Blue' look like in winter?

Hyacinth 'Delft Blue' is underground: it dies back after flowering and waits as a bulb until spring. Mark where it is, so a fork does not find it first.

Is hyacinth 'Delft Blue' good for bees and butterflies?

Hyacinth 'Delft Blue' is visited by bees.