Lupine Planting Methods and Key Technical Points

Lupine (Latin scientific name: Lupinus micranthus Guss.), also called "lupin", is a plant in the order Rosales, family Fabaceae, genus Lupinus. The stems are ascending or upright, branching from the base, and the whole plant is covered with brown or rust-colored stiff hairs. The raceme is terminal and relatively short; the infructescence axis thickens but remains no longer than the compound leaves. The flowering period is March to May, and the fruiting period is April to July.

Growing Environment

Lupine plants can grow up to about 70 cm tall and prefer environments with good ventilation and plenty of sunlight. They are not suited to hot environments and wilt easily; especially during the flowering period, heat can make the flowers dull and yellow. The soil requirements are not very strict, but deep soil is best, because lupine is a deep-rooted plant and cannot be grown in neutral or slightly alkaline soil, where it will grow poorly.

Planting Methods

Sowing

Lupine is propagated by seed, and can be sown in either spring or autumn. Spring sowing is done in March, but the growing period after spring sowing falls in summer, and the high heat can cause some varieties not to flower, or result in a low proportion of flowering plants and short flower spikes, giving a poor ornamental effect. Under natural conditions, autumn sowing flowers earlier and grows better than spring sowing; sow from September to mid-October, and the flowering period is April to June of the following year. Sow in 72-cell or 128-cell plug trays, one seed per cell, and cover. The seedling-raising soil should be loose and uniform, air-permeable and water-retentive; special seedling-raising soil, or a mix of peat and perlite, is best. Lupine seeds are fairly large, either plain or coated, at about 40 seeds per gram. The optimum germination temperature is around 25°C; keep the medium moist, and the seeds will emerge and germinate in 7-10 days, with a high germination rate.

Transplanting

The lupine seedling stage lasts 30-35 days. Once the true leaves have fully unfolded, transplant and divide the seedlings. Lupine has a well-developed root system; keep the original soil when transplanting to help the seedlings recover.

Soil

Based on the growing habits of lupine, controlling and adjusting the pH of the growing medium during cultivation is crucial for the normal growth and flowering of lupin. In general, a relatively simple and effective way to adjust it is to apply sulfur powder to the growing medium. Because sulfur needs a certain amount of time to decompose in the medium (about 40 days or more) before it takes effect, it should be applied as early as possible.

This is generally started after transplanting, when 2-3 true leaves have appeared, and the application rate depends on the original pH of the growing medium.

In addition, although acidic fertilizers such as ferrous sulfate and aluminum sulfate can lower the pH in the short term, excessively high salt ion concentrations can poison the plant roots, so they should be used less in production.

Repotting

Before final planting, repot 1-2 times depending on the growth condition. Tall bucket-shaped pots are best, to meet the growth needs of the taproot system, and a reasonable planting and placement density should be determined. For autumn-sown plants, appropriate cold protection measures should be taken over winter, with the temperature preferably above 5°C, to avoid frost damage to the leaves, which would affect early vegetative growth and the ornamental effect.

Disease Control

Lupine leaf spot disease produces brown to black lesions that harm leaf and stem growth and cause early leaf death. It can be sprayed with carbendazim wettable powder at 1500 times dilution, with good results. The symptoms begin on the leaves as small brown spots, which later form lesions 5-14 mm in diameter. The lesions merge into irregular brown patches, and the tissue dies. It mostly occurs in summer and autumn. The petioles, stems and sometimes petals can also be affected.

Precautions

Lupine prefers cool conditions, and since it is also a perennial plant, special attention should be paid to its care during high summer temperatures, to prevent yellowing leaves, stunted growth or even death caused by high heat, excessive moisture and scorching sunlight.

In landscaping, flowering lupines can also be planted directly among trees in woodland or in cool, ventilated spots, which makes summer care easier. After enjoying them as potted plants, promptly cut off the remaining flower spikes and dead old leaves, control fertilizer and water, and provide shade protection during the hot period to ensure they survive the summer safely.