Paeonia rockii is a precious tree peony variety, and its fertilization management needs to combine its growth habits and seasonal characteristics. Here are the key points of scientific fertilization:

The principle of fertilization

1. Give priority to organic fertilizer, supplemented by chemical fertilizer

Paeonia rockii is a fleshy root, so it is necessary to avoid burning the root with high concentration of chemical fertilizer. Priority should be given to composted organic manure (such as sheep manure and soybean cake fertilizer) to improve soil organic matter and water retention.

2. Don’t Overdo It

Excessive nitrogen fertilizer can lead to overgrowth of branches and leaves and reduce disease resistance, while excessive phosphorus and potassium fertilizer can cause micronutrient imbalance.

3. Pay attention to soil pH regulation

Optimum pH 6.5-7.5. The northern alkaline soil can be adjusted by adding humus soil, and the southern acidic soil can be adjusted by applying 50-100 grams of quicklime per square meter.

The scheme of applying fertilizer by stages

Base fertilizer (autumn, September-october)

Function: promote root system repair, reserve energy for overwintering.

Methods:

Ring ditches (20-30 cm deep) are dug around the outside of the plant.

3-5 kg organic fertilizer + 100g bone meal + 200g plant ash per plant.

After covering the soil, water through to promote the slow release of nutrients.

2. Germination fertilizer (in early spring, after the soil has thawed)

Function: promote the growth of new shoot and flower bud.

Solution:

Water the roots with 1:50 diluted rotten thin soybean cake, 2-3L per plant.

Spraying 0.2% Monopotassium phosphate foliar fertilizer twice every 10 days.

3. Fertilizer after flowering (may-june, within 2 weeks after flowering)

– key point: this is the critical period of flower bud differentiation, to be added in time.

Recipe:

Furrow application of NPK compound fertilizer (15-15-15)30g Plant + 5g iron(2+) sulfate (anhydrous)(to prevent yellow leaves).

Combine with intertillage to loosen soil, 5-8 cm depth to avoid root injury.

Control fertilizer in summer (July-august)

Note: high temperature dormant period stop applying quick-acting fertilizer, can be covered with 2 cm thick vermicompost moisture cooling.

5. Topdressing before overwintering (early November in north cold area)

Anti-freeze solution:

– rhizospheric compost (cow dung + rice husk, 1:1 ratio) with a thickness of 10 cm and covered with plastic film for thermal insulation.

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Handling of special problems

Leaf yellowing:

When the new leaves turned yellow, EDTA chelate iron (0.05% concentration) was sprayed twice with an interval of 7 days.

To shed a Bud:

Application of boron fertilizer (0.1% borax solution for root irrigation) at 30 days before anthesis combined with removal of lateral buds reduced nutrient competition.

Rejuvenation of a weakened plant:

Add seaweed fertilizer (including natural growth factor) every 20 days, 3 times in a row.

Iv. Taboo matters

1. avoid raw manure (immature manure can cause root rot) .

2. Avoid applying urea and other available nitrogen fertilizer during high temperature period in summer.

3. Avoid continuous rain in the surface sprinkle, to avoid nutrient loss.

By precisely regulating the fertilization nodes and ratios, the flowering quality of Paeonia rockii can be significantly improved, the single flowering period can be extended to 7-10 days, and the resistance of plants to gray mold and root-knot nematodes can be enhanced. It is recommended to dynamically adjust the fertilizer application rate in combination with soil EC value detection (suitable range 1.2-1.8 mS/cm) .